In patients tracked for as long as 20 years, the death rate from colorectal cancer was cut by 53 percent in those who had the test and whose doctors removed precancerous growths, known as adenomatous polyps, researchers reported on Wednesday in The New England Journal of Medicine. The test examines the inside of the intestine with a camera-tipped tube. “For any cancer screening test, reduction of cancer-related mortality is the holy grail,” said Dr. Gina Vaccaro, a gastrointestinal oncologist at the Knight Cancer Institute at Oregon Health and Science University who was not involved in the research. “This study does show that mortality is reduced if polyps are removed, and 53 percent is a very robust reduction.” Colorectal tumors are a major cause of cancer death in the United States and one of the few cancers that that can be prevented with screening. This year, more than 143,000 new cases and 51,000 deaths are expected. Incidence and death rates have been declining for about 20 years, probably because of increased use of screening tests and better treatments. But only about 6 in 10 adults are up to date on getting screened for colorectal cancer, according to federal estimates. Cancer screening tests have come in for greater scrutiny recently. A government panel recommended in October that men no longer get the P.S.A. blood screening test for prostate cancer after concluding it did not save lives. The new study on colonoscopy has limitations — it is not a randomized clinical trial — but some experts say it nonetheless was well done and helps answer questions about the effectiveness of the procedure. Earlier research had proved that removing precancerous polyps could greatly reduce the incidence of colorectal cancer. But a major question remained: Did removing the polyps really save lives? In theory, it was possible that doctors were finding growths that would not have killed the patient, or missing ones that could be fatal. “This study puts that argument to rest,” said Dr. David A. Rothenberger, a professor and deputy chairman of surgery at the University of Minnesota Masonic Cancer Center. He was not part of the study. Robert A. Smith, the senior director for cancer control at the American Cancer Society, said, “This is a very big deal.” A team of researchers led by Dr. Sidney J. Winawer, a gastroenterologist at Memorial Sloan-Kettering Cancer Center in New York City, followed 2,602 patients who had adenomatous polyps removed during colonoscopies from 1980 to 1990. Doctors compared their death rate from colorectal cancer with that of the general population, where 25.4 deaths from the disease would have been expected in a group the same size. But among the polyp group, there were only 12 deaths from colorectal cancer, which translates into a 53 percent reduction in the death rate. The new study did not compare colonoscopy with other ways of screening for colorectal cancer and so does not fully resolve a longstanding medical debate about which method is best. Tests other than colonoscopy look for blood in the stool or use different techniques to examine the intestine. All the tests are unpleasant, and people are often reluctant to have them. Although doctors have differed about which method is best, they agree that it is important to get over the squeamishness and have some type of test, usually starting at age 50. Screening is worthwhile because colorectal cancer is one of the few types of cancer (cervical and skin cancer are others) in which premalignant growths have been identified and the disease can be prevented if those growths are detected and cut out. Research indicates that not every polyp turns into cancer, but that nearly every colorectal tumor starts out as an adenomatous polyp. Even if intestinal cancer has already developed, it can still be cured if it is found early and treated. “Not all adenomas become cancers, and not all cancers cause death,” said Ann Zauber, the lead author of the study and a statistician at Sloan-Kettering. But in many cases, she said, “we have gotten those that would have had the potential to go on and cause a cancer death.” Dr. Smith, at the American Cancer Society, said the new study on colonoscopy was well done, and noted that changes in death rates can be difficult to measure because they require long-term studies like this one. But Dr. Harold C. Sox, an emeritus professor of medicine at Dartmouth Medical School and former editor of a leading medical journal, Annals of Internal Medicine, cautioned that the new study was not the last word. He said it was not clear that the same reduction in the death rate found in the study would occur in the general population. Nonetheless, he said, “I suspect that removing polyps does reduce colorectal cancer mortality.”
Hiển thị các bài đăng có nhãn Study. Hiển thị tất cả bài đăng
Hiển thị các bài đăng có nhãn Study. Hiển thị tất cả bài đăng
Thứ Năm, 23 tháng 2, 2012
Study: Colonoscopy cuts colon cancer death risk
LOS ANGELES (AP) — Millions of people have endured a colonoscopy, believing the dreaded exam may help keep them from dying of colon cancer. For the first time, a major study offers clear evidence that it does.
Removing precancerous growths spotted during the test can cut the risk of dying from colon cancer in half, the study suggests. Doctors have long assumed a benefit, but research hasn't shown before that removing polyps would improve survival — the key measure of any cancer screening's worth.
Some people skip the test because of the unpleasant steps need to get ready for it.
"Sure, it's a pain in the neck. People complain to me all the time, 'It's horrible. It's terrible,'" said Dr. Sidney Winawer, a gastroenterologist at Memorial Sloan-Kettering Cancer Center in New York who helped lead the study. "But look at the alternative."
A second study in Europe found that colonoscopies did a better job of finding polyps than another common screening tool — tests that look for blood in stool. Both studies were published in Thursday's New England Journal of Medicine.
Colorectal cancer is the second leading cause of cancer death in the United States and the fourth worldwide. More than 143,000 new cases of cancers of the colon or rectum are expected in the U.S. this year and nearly 52,000 people will die from it, according to the American Cancer Society.
Deaths from colorectal cancer have been declining for more than two decades, mostly because of screening including colonoscopies and other tests, the organization says. People of average risk of colon cancer ages 50 to 75 should get screened, but only about half in the U.S. do.
A government-appointed panel of experts recommends one of three methods: annual stool blood tests; a sigmoidoscopy (scope exam of the lower bowel) every five years, plus stool tests every three years; or a colonoscopy once a decade.
In a colonoscopy, a thin, flexible tube with a tiny camera is guided through the large intestine. Growths can be snipped off and checked for cancer. Patients are sedated, but many dread the test because it requires patients to eat a modified diet and drink solutions the day before to clear out the bowel. It usually costs more than $1,000, compared with a $20 stool test.
Researchers at Sloan-Kettering previously showed that removing polyps during colonoscopy can prevent colon cancer from developing, but it was not clear whether it saved lives.
The new study followed 2,602 patients who had precancerous growths removed during colonoscopies for an average of 15 years. Their risk of dying from colon cancer was 53 percent lower than what would be expected among a similar group in the general population — 12 patients followed in the study died, versus 25 estimated deaths in the general population.
The study was not a randomized trial that's the gold standard in medical research. But Robert Smith, director of screening at the American Cancer Society, said it's the first direct evidence that removing polyps can reduce the risk of colon cancer death.
"There's no question that these are findings that we can take to the bank," said Smith, who had no role in the research.
The National Cancer Institute and several cancer organizations paid for the study.
Government and private cancer groups also funded the second study in the journal, led by researchers in Spain. About 53,000 participants were given a colonoscopy or a stool blood test. Both tests found similar numbers of colon cancer cases — about 30 in each group.
However, colonoscopies found advanced growths in twice as many people — 514 versus 231 of those given the stool test. Colonoscopy also found 10 times more people with less serious growths than the stool test did.
Neither test proved very appealing — only a quarter of patients offered a colonoscopy had one. Similarly, only a third agreed to the offered stool test.
The Spanish study is continuing and similar research in the U.S. and Norway that began recently is looking at the long-term impacts of colonoscopy.
Stephen Raquet, of Mount Kisco, N.Y., finds the test reassuring even if the preparation is unpleasant. He had his first colonoscopy 13 years ago at age 41, earlier than usual because of a family history of colon cancer.
The sudden death of his 45-year-old sister from the disease prompted Raquet to get checked out. He had a precancerous growth removed at Memorial Sloan-Kettering in 1999, and has had the test every three years since.
During his last appointment four months ago, doctors said he can come back in five years.
"It's given me peace of mind," said the 54-year-old business executive.
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Online:
Guidelines: http://www.uspreventiveservicestaskforce.org/uspstf/uspscolo.htm
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Follow Alicia Chang's coverage at http://www.twitter.com/SciWriAlicia
Colon cancer study backs blood stool screening test
NEW YORK (Reuters Health) - Although colon cancer screening is recommended by many organizations, less clear is which method is best to detect tumors and precancerous lesions. A new study in the New England Journal of Medicine suggests that a relatively inexpensive and non-invasive test may be just as effective as a colonoscopy.
Meanwhile, a 23-year study, also published in the journal, has confirmed that removing precancerous polyps, known as adenomas, during a colonoscopy can reduce the risk of death from colorectal cancer by half.
In an editorial in the Journal, Dr. Michael Bretthauer of Oslo University Hospital and Dr. Mette Kalager of Telemark Hospital, both in Norway, said that based on the results, "an appealing concept would be to use colonoscopy as a triage screening test, offering it once for everybody at 60 years of age" and using it to classify people into high- and low-risk categories. Low-risk people would not need further screening while those with adenomas would be evaluated regularly.
One in 20 Americans will develop colorectal cancer. About 140,000 cases are diagnosed in the United States each year, resulting in about 49,000 deaths, according to the National Cancer Institute. It is the third most common cancer worldwide.
Currently, the U.S. Preventive Services Task Force, a government-backed agency, recommends screening for people age 50 to 75 years by one of three methods: a colonoscopy every 10 years; annual stool testing; or a less-thorough look into the colon (known as flexible sigmoidoscopy) every five years in conjunction with stool testing every two to three years.
People often find the tests unpleasant, however.
For example, in the new study that compared stool testing with colonoscopy, only 34 percent went along with stool testing. The participation rate was even lower when colonoscopy was offered, even though doctors can use it to cut away those suspicious precancerous adenomas.
In theory, adenoma removal saves lives by preventing a tumor. Ann Zauber of the Memorial Sloan-Kettering Cancer Center in New York, chief author of the long-term evaluation of polyp removal, and her colleagues said their work demonstrates that.
"This study is showing both a reduction in colon cancer incidence and colon cancer deaths by removing the adenomas, and it's a long-term effect" she told Reuters Health in a telephone interview. "This is reassuring for people to come in for screening."
The conclusion is based on people who were sent for a colonoscopy between 1980 and 1990. The Zauber team compared their death rate to the estimated death rate from the Surveillance Epidemiology and End Results (SEER) program.
Over a period as long as 23 years, the rate from colorectal cancer among the 2,602 people who originally had adenomas removed was 53 percent lower than estimated from the SEER data. In all, 12 died from cancer in the removal group, while 25 had normally been expected to die of colorectal disease.
The lower rate includes the fact that 81 percent of the patients who had polyps removed continued to have periodic colonoscopies to check for growths.
Bretthauer and Kalager cautioned in their editorial that "the study mimics a situation in which 100 percent of the population complies with screening, which is not a real-life scenario."
CHEAPER, LESS INVASIVE TEST PERFORMS WELL
The COLONPREV study, being conducted in Spain, is designed to compare 10-year death rates in two groups: volunteers who received a one-time colonoscopy and volunteers who are being screened every two years using fecal immunochemical testing (FIT), a form of blood stool testing. A positive FIT test led to a colonoscopy.
After the first round of testing, the researchers report in the New England Journal of Medicine, colorectal cancer was found in 30 people in the 26,703-member colonoscopy group and 33 in the 26,599-person FIT group.
Colonoscopy uncovered twice as many advanced adenomas, about two percent of the sample vs. one percent.
But the chief author of the Spanish study, Enrique Quintero of Hospital Universitario de Canarias, told Reuters Health by phone that it was encouraging that the cheaper fecal test "detected half the advanced adenomas just in the first round."
The next round of FIT tests will uncover more growths, he predicted.
Death rates will not be examined until the 10-year followup is completed in 2021.
Quintero and his team also found that the people assigned to the FIT group were more likely to participate in screening than those who were in line for a colonoscopy.
The participation rates were 34 percent with the stool-sampling test compared to 25 percent for colonoscopy.
At this point in the study, the researchers concluded, "the numbers of subjects who needed to be screened to find one colorectal cancer were 191 in the colonoscopy group and 281 in the FIT group, and the numbers who needed to be screened to find any advanced (cancer) were 10 and 36."
That's important when the FIT test is so much cheaper than a colonoscopy, Quintero said. "This simple, non-invasive and cheap test is equally good at detecting colorectal cancer and identifying the high-risk individual that should undergo a colonoscopy."
And the complication rate, including bleeding, low blood pressure and slow heartbeat, was nearly five times higher in the colonoscopy group.
SOURCES: http://bit.ly/xJBNxg and http://bit.ly/xPLSv4 New England Journal of Medicine, February 23, 2012.
Colon cancer study backs blood stool screening test
NEW YORK (Reuters Health) - Although colon cancer screening is recommended by many organizations, less clear is which method is best to detect tumors and precancerous lesions. A new study in the New England Journal of Medicine suggests that a relatively inexpensive and non-invasive test may be just as effective as a colonoscopy.
Meanwhile, a 23-year study, also published in the journal, has confirmed that removing precancerous polyps, known as adenomas, during a colonoscopy can reduce the risk of death from colorectal cancer by half.
In an editorial in the Journal, Dr. Michael Bretthauer of Oslo University Hospital and Dr. Mette Kalager of Telemark Hospital, both in Norway, said that based on the results, "an appealing concept would be to use colonoscopy as a triage screening test, offering it once for everybody at 60 years of age" and using it to classify people into high- and low-risk categories. Low-risk people would not need further screening while those with adenomas would be evaluated regularly.
One in 20 Americans will develop colorectal cancer. About 140,000 cases are diagnosed in the United States each year, resulting in about 49,000 deaths, according to the National Cancer Institute. It is the third most common cancer worldwide.
Currently, the U.S. Preventive Services Task Force, a government-backed agency, recommends screening for people age 50 to 75 years by one of three methods: a colonoscopy every 10 years; annual stool testing; or a less-thorough look into the colon (known as flexible sigmoidoscopy) every five years in conjunction with stool testing every two to three years.
People often find the tests unpleasant, however.
For example, in the new study that compared stool testing with colonoscopy, only 34 percent went along with stool testing. The participation rate was even lower when colonoscopy was offered, even though doctors can use it to cut away those suspicious precancerous adenomas.
In theory, adenoma removal saves lives by preventing a tumor. Ann Zauber of the Memorial Sloan-Kettering Cancer Center in New York, chief author of the long-term evaluation of polyp removal, and her colleagues said their work demonstrates that.
"This study is showing both a reduction in colon cancer incidence and colon cancer deaths by removing the adenomas, and it's a long-term effect" she told Reuters Health in a telephone interview. "This is reassuring for people to come in for screening."
The conclusion is based on people who were sent for a colonoscopy between 1980 and 1990. The Zauber team compared their death rate to the estimated death rate from the Surveillance Epidemiology and End Results (SEER) program.
Over a period as long as 23 years, the rate from colorectal cancer among the 2,602 people who originally had adenomas removed was 53 percent lower than estimated from the SEER data. In all, 12 died from cancer in the removal group, while 25 had normally been expected to die of colorectal disease.
The lower rate includes the fact that 81 percent of the patients who had polyps removed continued to have periodic colonoscopies to check for growths.
Bretthauer and Kalager cautioned in their editorial that "the study mimics a situation in which 100 percent of the population complies with screening, which is not a real-life scenario."
CHEAPER, LESS INVASIVE TEST PERFORMS WELL
The COLONPREV study, being conducted in Spain, is designed to compare 10-year death rates in two groups: volunteers who received a one-time colonoscopy and volunteers who are being screened every two years using fecal immunochemical testing (FIT), a form of blood stool testing. A positive FIT test led to a colonoscopy.
After the first round of testing, the researchers report in the New England Journal of Medicine, colorectal cancer was found in 30 people in the 26,703-member colonoscopy group and 33 in the 26,599-person FIT group.
Colonoscopy uncovered twice as many advanced adenomas, about two percent of the sample vs. one percent.
But the chief author of the Spanish study, Enrique Quintero of Hospital Universitario de Canarias, told Reuters Health by phone that it was encouraging that the cheaper fecal test "detected half the advanced adenomas just in the first round."
The next round of FIT tests will uncover more growths, he predicted.
Death rates will not be examined until the 10-year followup is completed in 2021.
Quintero and his team also found that the people assigned to the FIT group were more likely to participate in screening than those who were in line for a colonoscopy.
The participation rates were 34 percent with the stool-sampling test compared to 25 percent for colonoscopy.
At this point in the study, the researchers concluded, "the numbers of subjects who needed to be screened to find one colorectal cancer were 191 in the colonoscopy group and 281 in the FIT group, and the numbers who needed to be screened to find any advanced (cancer) were 10 and 36."
That's important when the FIT test is so much cheaper than a colonoscopy, Quintero said. "This simple, non-invasive and cheap test is equally good at detecting colorectal cancer and identifying the high-risk individual that should undergo a colonoscopy."
And the complication rate, including bleeding, low blood pressure and slow heartbeat, was nearly five times higher in the colonoscopy group.
SOURCES: http://bit.ly/xJBNxg and http://bit.ly/xPLSv4 New England Journal of Medicine, February 23, 2012.
Chủ Nhật, 19 tháng 2, 2012
Men opting for costly new prostate cancer treatment, study shows
Lindsey Konkel
NEW YORK (Reuters Health) - Men diagnosed with localized prostate cancer are more likely to be treated with proton beam therapy, a novel form of radiation therapy, if the technology is available nearby, a new study found.
Prostate cancer is the most common cancer in men -- the National Cancer Institute estimates that more than 240,000 men in the U.S. were diagnosed in 2011.
About nine out of 10 of those cases were localized prostate cancer, meaning the cancer hasn't spread outside the prostate gland. Nearly all men diagnosed with localized tumors survive at least five years after diagnosis.
In the study, researchers examined the treatment choices of nearly 20,000 men living inside or outside of a regional market for Loma Linda University, a hospital in Southern California with a proton beam facility. All men were diagnosed with low- to intermediate-risk prostate cancer between 2003 and 2006.
Currently, there are nine proton centers in operation in the United States and eight more in development, according to the National Association for Proton Therapy.
Touted as a technological advancement over other forms of radiation therapy, proton beam therapy allows radiated particles to more tightly target and destroy tumor cells, leaving more of the surrounding tissue intact.
The treatment is often billed as having lower impotence and incontinence rates than other radiation treatment options, but there's a lack of evidence to support this, according to Dr. David Aaronson, a urologist at Kaiser Permanente Medical Group in Oakland, California, and lead author of the study.
After taking into account factors such as tumor stage and year of diagnosis, Aaronson's team found that patients living near a proton beam facility were more than five times more likely to receive proton beam treatment than those living outside of the hospital's referral region.
Nearly nine percent of the patients living within the referral region for the facility received proton beam therapy, compared to less than two percent of patients throughout the rest of the state.
The researchers also found that younger and non-Hispanic white men were also slightly more likely to receive proton beam treatment.
"It's not surprising that men are more likely to be treated with a certain technology in an area where that technology is offered," Aaronson told Reuters Health.
While most insurers, including Medicare, cover proton beam therapy, it comes at a hefty price.
Previous studies have estimated that proton beam therapy costs twice as much as intensity-modulated radiation therapy, another form of external radiation therapy and about five times more than radioactive seed implants.
And side-by-side comparisons of proton beam therapy and other prostate cancer treatments have not been done, according to Dr. Leonard Lichtenfeld, chief medical officer for the American Cancer Society.
Despite the added costs, there's no evidence to suggest that proton beam therapy results in better outcomes than other forms of prostate cancer treatment, including other forms of radiation, surgery or hormone therapy.
Although proton beam therapy has been shown to be superior in targeting tumors of the brain, eye and spine, those cancers are rare.
Institutions with proton beam facilities often look to pad their numbers by treating prostate cancer, according to Dr. Anthony Zietman, a radiation oncologist at Massachusetts General Hospital in Boston who was not involved in the new study.
"People often think that technology is synonymous with 'better,' but in some cases, it's not," said Aaronson.
"With the healthcare crisis looming and multiple treatment options available, newer, more expensive procedures for prostate cancer should be validated before they are implemented," he said.
SOURCE: http://bit.ly/yHdxqN Archives of Internal Medicine, February 13, 2012
Kids With Crohn's Disease, Colitis Often Struggle at School: Study
FRIDAY, Feb. 17 (HealthDay News) -- Children with inflammatory bowel disease may have difficulty in school due to frequent absences that are largely the result of mental struggles such as depression rather than the disease itself, a new study finds.
Researchers from Nationwide Children's Hospital in Columbus, Ohio, had students aged 11 to 17 years with and without inflammatory bowel disease -- which generally takes the form of Crohn's disease or ulcerative colitis -- answer questionnaires about their mental health, school functioning and quality of life. Schools provided report cards and school absence information.
Children with the condition missed more days of school than healthy kids, and those who missed lots of school had lower grade point averages, according to the study.
Kids with inflammatory bowel disease were also at risk of "internalizing" problems, such as depression, according to the study. Kids who were struggling more mentally also tended to have more absences.
"Youth with [inflammatory bowel disease] are at increased risk for depression, so the finding that internalizing problems are associated with school absence is a particular concern with important implications," said lead study author Laura Mackner, an investigator in the hospital's Center for Biobehavioral Health, in a hospital news release.
The study recently appeared in the Journal of Developmental & Behavioral Pediatrics.
Symptoms of inflammatory bowel disease include abdominal pain, fatigue and diarrhea. Children may be prescribed corticosteroids, which may affect learning and memory, or have to take intravenous medication requiring hours in an infusion clinic, according to Dr. Wallace Crandall, director of the hospital's Center for Pediatric and Adolescent Inflammatory Bowel Disease.
"Both [inflammatory bowel disease] and its treatment have the potential to disrupt school functioning," Crandall said in the release.
The study authors noted that most of the children studied were in remission or had only a mild form of the disease, so it's unclear if their findings would apply to children with more severe cases.
More information
Nemours has more on inflammatory bowel disease.
Few rheumatoid arthritis clinical trials compare drugs: study
NEW YORK (Reuters Health) - To test whether a new drug is an improvement over existing treatments, the ideal clinical trial would compare the medications head to head, but few trials of rheumatoid arthritis treatments happen that way, according to a new study.
Instead, researchers found that for certain new rheumatoid arthritis medications, subjects in the comparison groups were often assigned to continue taking a drug that didn't help them or to take a fake drug called a placebo -- in both cases effectively depriving those patients of treatment for their disease.
"Of course it's easier to compare to a placebo than an active treatment but in no way can it justify exposing patients to irreversible morbidity," said Dr. Candice Estellat at the French national medical research institute, INSERM, who led the study.
Her concern is that if studies don't compare a new drug to other effective ones, people's conditions will persist or even worsen throughout the study.
Additionally, without so-called head-to-head trials, doctors will have little evidence to go on to determine whether one treatment is better than another, Estellat said.
Rheumatoid arthritis is an autoimmune disease that causes inflammation and damage to joints.
About 1.5 million adults have the painful disorder, and they typically require lifelong treatment with physical therapy or medications, such as methotrexate.
The newest forms of rheumatoid arthritis medications to become available are called biologic disease-modifying antirheumatic drugs (DMARDs).
These include the brand-name medications Enbrel and Humira. They come in the form of an injection, and cost around $15,000 per year.
Estellat and a colleague gathered information on all clinical trials of biologic DMARDs registered with the U.S. government's clinicaltrials.gov website and that were ongoing between 2002 and 2009.
She said they decided to do the study after hearing from specialists about the lack studies comparing these new drugs against other biologic DMARDs.
Of the 91 trials they identified, just five studies compared one biologic medication to another.
"Unfortunately we were not surprised as it confirms rheumatologists' feeling(s)," Estellat said.
The remaining trials will not provide doctors and patients with information for making evidence-based decisions, she and her coauthor write in the Archives of Internal Medicine.
"There (are) plenty of studies to show that A is better than placebo, B is better than placebo, C is better than placebo but so few to know which one is the best between A, B or C," Estellat told Reuters Health by email.
Not only are placebo-compared experiments less useful in understanding how well a drug works compared to others, but, the report points out, they may violate international ethical research standards and specific guidelines from the American College of Rheumatology if people are not given treatment for a serious condition like rheumatoid arthritis.
The 91 trials included 102 comparisons of a biologic medication against something else -- in most cases that something else was a placebo or a treatment previously shown not to work for them.
"Despite recommendations to give biologic treatments to patients with an inadequate response to conventional treatment, 9,879 patients were or will be randomized to control arms to receive no treatment or their previous ineffective treatment," Estellat said.
Studies on humans have to go through ethical scrutiny by independent bodies called institutional review boards, and in the U.S. they must also be approved by the Food and Drug Administration.
A spokesperson for the pharmaceutical trade group, PhRMA, wrote in an email to Reuters Health that "much of that decision-making is done under the guidance of FDA, whose experts are able to work with companies to evaluate the pros and cons of different types of trials."
Dr. Steven Pearson, the president of the Institute for Clinical and Economic Review in Boston, explained the possible reasons for not using head-to-head trials for certain drugs in an editorial accompanying Estellat's study.
He agreed that using placebos is a less desirable trial design to ultimately help physicians determine which medication they should prescribe for their patients, but said it's a trade-off for making an experiment less difficult.
"For one, having an active agent against a comparator would require many more patients," he told Reuters Health.
"In order to be able to get clear signals of the safety and effectiveness of new agents it's going to be easiest to compare it to a placebo, in terms of costs and duration," Pearson added.
To be most useful to patients and physicians, clinical trials need to compare one drug to another, and Pearson said that companies, regulators and researchers should think of creative ways to do so without having the studies become prohibitively expensive or unwieldy.
"I think the study is helpful to (the Food and Drug Administration) and others to take stock and see if there are other innovative study designs and approaches that allow more head-to-head trials," Pearson said.
Estellat said that people involved in clinical studies "have to imagine original designs to conciliate ethics and scientific requirements."
SOURCE: http://bit.ly/yh1orf Archives of Internal Medicine, February 13, 2012.
Contagious Cancer: Genome Study Reveals How Tasmanian Devil Cancer Has Spread
tasmanian_devil_cancer_genome Image courtesy of Save the Tasmanian Devil ProgramA killer cancer that is threatening to wipe Tasmanian devils off the map for good has been spreading from an original infected female 15 years ago via live cancer cells, according to evidence from genome sequences of the cancer and the animal, published online Thursday in Cell. Finding out how this happened could help save this species from extinction and it could also prepare researchers for the unlikely event that a contagious cancer ever appeared in humans.
The facial cancer, which is spread through bites, has plagued this animal’s precarious population for more than a decade. Tasmanian devils (Sarcophilus harrisii) are the largest surviving carnivorous marsupials and live on Australia’s island state Tasmania. [Read more about this scourge in "The Devil's Cancer," from Scientific American's June 2011 issue.] All of the tumors afflicting the animals today contain cells from one original devil, genetic sequences show. “I call her the immortal devil,” Elizabeth Murchison, a researcher at the Wellcome Trust Sanger Institute and co-author of the new paper, said in a prepared statement. “Her cells are living on long after she died.”
An earlier version of the Tasmanian devil genome was published last year in Proceedings of the National Academy of Sciences and revealed some secrets about why the cancer hasn’t killed off the species already. One of the two devils sequenced, named Cedric, showed resistance to at least two strains of the cancer, although he later succumbed to a third.
“The Tasmanian devil cancer is the only cancer that is threatening an entire species with extinction,” Murchison said. After the first tumor appears on the doomed animals face, it will likely die within three months.
But by turning to genetics, researchers and conservationists hope to be able to find clues to at least slow the cancer’s spread. The researchers studied tumors from 104 tumors collected from Tasmanian devils from various locations on the island and found that there were separate geographic groups of cancer types but that all of them contained cells from the original female. “Sequencing the genome of this cancer has allowed us to catalogue the mutations that caused this cancer to arise and to persist,” Murchison said. More detailed genetic details could point the way to targeted cancer drugs. It might also suggest how the cancer is able to sneak past the immune system and start its explosive growth so quickly.
“Tracing the evolutionary history and spread of this cancer helps us to understand not only what caused this disease but also to predict how it might behave in the future,” David Bentley, chief scientist at Illumina Cambridge, Ltd. and study co-author, said in a prepared statement.
The Tasmanian devil’s cancer has more than 17,000 mutations. “This is fewer mutations that are found in some human cancers and indicates that cancers do not need to be extremely unstable in order to become contagious,” Bentley said. Only one other type of contagious cancer is known a venereal tumor that infects dogs and wolves. The next step is “to use the genome sequence to understand more about how this cancer became transmissible,” Michael Stratton, director of the Wellcome Trust Sanger Institute and study co-author, said in a prepared statement. “Cancers that transmit through populations are obviously incredibly rare, he said, but we should use the Tasmanian devil example to be prepared in the extremely unlikely event that such an epidemic ever occurs in humans.”
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Bird flu study publication gets go-ahead after security check
Bird flu experts meeting in Geneva ruled that controversial research on a mutant form of the virus potentially capable of being spread among humans should be made public.
Security assessments must however be carried out first before the two studies can be published and the research can continue, scientists agreed at a two-day meeting at the World Health Organization.
"The consensus was that in the interest of public health the full papers should be published," said Professor Ron Fouchier from the Institute of Virology in the Netherlands, the scientist behind one of the studies.
US bio-security chiefs urged in November that key details of the papers remain unpublished, citing fears of a pandemic should a mutated H5N1 virus escape the laboratory.
Scientists agreed on January 20 to a 60-day moratorium on further studies.
That deadline will now be extended for an unspecified time to allow for a wider group of scientists to examine the risks and allow for public discussion, Fouchier said at a conference following the meeting.
"This is very important research that needs to move forward," he said.
"The question is, how can it be done safely, what about bio-security, how do we prevent access to bad people?"
"Once there's agreement on all those issues then we can continue our work."
The 22 participants included the two teams of researchers and representatives of the scientific journals Science and Nature who were asked to withhold publication.
The editor of the US journal Science said later Friday he supports the decision of the bird flu experts in Geneva.
"The supreme court of decision-making on these things should not be me," said Bruce Alberts, editor-in-chief of Science, which along with the British journal Nature had been on track to publish partial versions of the research in March.
Alberts said the two journals were working closely with each other and with authorities, and would await further information before making plans to publish the manuscripts in full in the months ahead.
"Many people in the government worked very hard to try to see whether they could develop a mechanism that could be used to selectively get redacted information to the right people, and they came across all kinds of difficulties."
The engineered virus, created by two separate research teams in the Netherlands and Wisconsin, was able to spread through the air among mammals, indicating it could potentially be deadly to humans on a massive scale.
Alberts said he hoped that the decision taken after the two-day Geneva meeting would lead to the creation of an international body of scientists and biosecurity experts for making future decisions on such matters.
"The very best possible outcome for this is the establishment of an international version of the NSABB," he said, referring to the National Science Advisory Board for Biosecurity, a US advisory panel that urged the government, which had funded the research, to withhold key details from publication.
However, NSABB leaders said last year that an international decision was needed and that they would obey any decision agreed by the global science community.
Avian influenza H5N1 is primarily transmitted between birds and very rarely to humans.
The Dutch team and another from the University of Wisconsin in the United States found ways late last year to engineer the virus so that it could be transmitted among mammals.
The breakthrough raised alarm that the method could fall into the wrong hands and unleash a massive flu pandemic that could cost millions of lives.
The WHO said 345 people have died from H5N1 from a total of 584 cases in 15 countries. The majority of victims have been in Indonesia.
"Given the high death rate associated with this virus all participants at the meeting emphasised the high level of concern with this flu virus in the scientific community and the need to understand it better with additional research," said Dr Keiji Fukuda, WHO assistant director general of health security.
The body underlined the need to increase public understanding of the research and to review bio-security issues.
The WHO will host further meetings "soon" with a wider range of scientists.
"This was a group of experts on influenza research," said Fouchier.
"We need to consult with the broader scientific community."
Thứ Ba, 7 tháng 2, 2012
Diabetes Takes Toll on Women's Hearing: Study
FRIDAY, Feb. 3 (HealthDay News) -- Diabetes is associated with hearing loss in women, especially if the blood sugar disease isn't well-controlled, new research indicates.
The study, done by researchers at Henry Ford Hospital in Detroit, examined the medical records of 990 men and women who had hearing tests between 2000 and 2008. Patients with diabetes were divided into two groups: well-controlled and poorly controlled.
Among women aged 60 to 75, hearing loss was 14 percent worse even in well-controlled diabetics compared to those without diabetes. That is not a clinically significant loss, noted study author Dr. Kathleen Yaremchuk, chairwoman of the department of otolaryngology at the Henry Ford Healthcare System in Detroit.
"An individual might not notice it," Yaremchuk said.
On the other hand, poorly controlled diabetics' hearing was 28 percent worse than the non-diabetic group's hearing.
Younger women who had diabetes, well-managed or not, were more likely to have hearing loss than those unaffected by the illness, the study found.
Diabetes is known to affect the eyes, kidneys and other organs, Yaremchuk said. "Our study shows it can affect hearing as well."
In the study, presented recently at the Triological Society's annual meeting in Miami Beach, Fla., there was no link between hearing loss among men and diabetes, whether it was well-managed or not. Men are more likely in general to suffer from hearing loss than women, so the prevalence of the condition among males may mask diabetes' effect, the study suggested.
Men are exposed to more environmental causes of hearing loss, such as loud noise, either in the workplace or during leisure activities, such as attending large sporting events, explained Yaremchuk.
Managing diabetes properly should help prevent hearing loss or keep it from getting worse, Yaremchuk said.
What's unknown is if better management of diabetes can reverse hearing loss that's already occurred.
"We do not know if losing weight and improving control of diabetes will reverse the hearing loss that is seen. However, it will stop progression of the hearing loss," she said.
Recommendations call for diabetics' to have their vision checked every year, said Dr. Spyros Mezitis, a clinical endocrinologist at Lenox Hill Hospital in New York City.
This latest finding suggests diabetics may also need to have their hearing tested, Mezitis said.
"This study will help make doctors more aware to ask about hearing, particularly in women between 60 and 75," said Mezitis, also an assistant professor of clinical medicine at New York Presbyterian Hospital-Cornell Medical Center.
About 26 million Americans have diabetes, mostly type 2, which is associated with obesity.
Because this study was presented at a medical meeting, the conclusions should be viewed as preliminary until published in a peer-reviewed journal.
More information
To learn more about diabetes, visit U.S. National Institutes of Health.
Breast Cancer Drug May Weaken Bones, Study Finds
TUESDAY, Feb. 7 (HealthDay News) -- A drug used to prevent breast cancer in women at high risk for the disease appears to cause bone loss in some postmenopausal women, a new study finds.
The drug, Aromasin (exemestane), has been shown to reduce the odds of breast cancer by 65 percent, but it also worsens bone density by about three times in older women who are taking it, Canadian researchers report.
"The drug did affect bone density at the hip and spine," said lead researcher Dr. Angela Cheung, a senior scientist at the University Health Network in Toronto. "It does not affect everyone; about 65 percent of women have some bone loss."
The fear of bone loss is not a reason not to take the drug, Cheung said. "You really need to pay attention to your bone health when you take this medication, especially for preventing breast cancer."
However, for women who are at high risk for fractures, other drugs should be considered, she added.
Women taking this drug should also be taking calcium and vitamin D supplements, and having their bone density monitored, Cheung said.
An older drug, tamoxifen, actually builds bone, but it is not as effective at preventing breast cancer, she said. "But, for someone with healthy bones it is worthwhile taking the medication."
Exemestane is an aromatase inhibitor and works by suppressing the female hormone estrogen. These drugs are standard treatment for postmenopausal women with early stage hormone-receptor-positive breast cancer.
It had been speculated that exemestane, a third-generation aromatase inhibitor, might result in less bone loss than other similar drugs and might even stimulate bone formation.
For the new study, Cheung's team looked at bone loss among the more than 4,500 women who took part in a trial that compared exemestane with a placebo.
Among women taking the drug, the risk of developing breast cancer was lowered 65 percent, compared with women taking a placebo.
Among the 351 women in whom bone loss was studied, the researchers found that after two years there was an 8 percent loss of cortical bone in women taking exemestane, compared with 1 percent in the placebo group.
Cortical bone is the outer shell of bone that provides most of the bone support, and its loss accounts for about 80 percent of fractures in older people, the researchers noted.
The findings were published in the Feb. 6 online edition of The Lancet Oncology.
Dr. Stephanie Bernik, chief of surgical oncology at Lenox Hill Hospital in New York City, was somewhat cautious about the new research. She said that "the study needs longer follow-up to see if there is an increased risk of fracture."
"This study doesn't mean that we should stop using these drugs," she said. "We certainly rely on aromatase inhibitors more than tamoxifen in postmenopausal women, because the survival benefit has been proven."
The benefit of the drug outweighs that risk for most women, she said. However, if there is a family history of osteoporosis it may not be the best choice, Bernik said.
More information
For more on breast cancer, visit the American Cancer Society.
Booze and Family History of Colon Cancer a Bad Mix: Study
FRIDAY, Feb. 3 (HealthDay News) -- People who consume a few alcoholic drinks a day and have a family history of colorectal cancer are at increased risk for developing colon cancer, new research suggests.
For the study, researchers in Boston examined data from more than 87,000 women in the Nurses' Health Study and 47,000 men in the Health Professionals Follow-up Study, and found that 1,801 cases of colon cancer were diagnosed among the participants from 1980 onward.
People with a family history of colorectal cancer who drank an average of 30 or more grams of alcohol per day (about 2.5 typical drinks in the United States) were at increased risk for colon cancer, according to lead author Eunyoung Cho, of the Channing Laboratory, department of medicine at Brigham and Women's Hospital and Harvard Medical School, and colleagues.
Those at greatest risk also ate the most red meat, smoked more and consumed the least folate, which suggests they ate fewer green vegetables and cereal. The findings indicate that other lifestyle factors, such as diet, play an important role in colon cancer risk, the researchers said.
Although the study uncovered an association between these factors and colon cancer risk, it did not prove a cause-and-effect relationship.
Among people who did not have a family history of colorectal cancer, no significant association was found between alcohol consumption and colon cancer. Greater alcohol intake was not associated with a consistent increase in cancer risk, the authors noted in a news release from Boston University Medical Center.
The study was published in the February issue of the American Journal of Clinical Nutrition.
More information
The American Cancer Society has more about colorectal cancer.
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