Soy Supplements May Not Shield Against Breast Cancer

FRIDAY, Feb. 3 (HealthDay News) -- Soy supplements do not protect women against breast cancer, a new study suggests.

The findings are consistent with the results of previous studies that examined the cancer prevention benefits of the dietary supplements, said lead researcher Dr. Seema Khan, a professor of surgery at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University.

The study included 98 women who were randomly assigned to receive a mixed soy isoflavones supplement or placebo. Isoflavones are components of soy foods thought to have anti-estrogen activity (estrogen is "fuel" for many breast cancers).

After six months, the researchers examined levels of Ki-67 -- a protein marker of cancer cell growth -- in certain breast cancer cells taken from the women. Overall, there were no differences in Ki-67 levels between women who took the soy supplement and those who took the placebo.

However, the level of Ki-67 increased from 1.71 to 2.18 in premenopausal women taking the soy supplement, which suggests the supplement might even have a negative effect, according to the study published in February issue of the journal Cancer Prevention Research.

"This was a small finding," Khan stressed in a news release from the American Association for Cancer Research, "but one that should suggest caution."

"Simply put, supplements are not food. Although soy-based foods appear to have a protective effect, we are not seeing the same effect with supplementation using isolated components of soy, so the continued testing of soy supplements is likely not worthwhile," Kahn concluded.

But one expert said the study, while valuable, had limitations.

Dr. Patrick Borgen, director of Breast Cancer Care Services at the Maimonides Cancer Center in New York City, called the study "thought provoking and well-executed."

But he added that uncertainties remain. For example, the area of the breast from which the cells were taken and studied matters, because cancer develops in different ways across the geography of the breast. Furthermore, other potential risk factors, such as diet, exercise, alcohol intake and stress, could play a role in the women's breast cancer risk as well and "are extremely hard to control for in this kind of study," Borgen said.

Finally, Borgen said, it is still difficult to predict the "long-term consequences" of the cell changes captured by Ki-67 testing.

For all of those reasons, "the conclusions -- that further study may not be warranted or that use of these supplements in premenopausal women may be dangerous -- should therefore be taken in the context of the limitations of the study," Borgen said.

More information

The U.S. National Library of Medicine has more about soy.

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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.

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Breast cancer kills older women more often

NEW YORK (Reuters Health) - Breast cancer is often considered more deadly among younger women, but a new study shows older women are actually more likely to die of the disease.

Researchers found that among women who had been diagnosed with a certain type of breast cancer, those over 75 years old were 63 percent more likely to die of the cancer than women younger than 65.

"I suspect it's undertreatment," said Dr. Stephen Jones, one of the authors of the study and the medical director at US Oncology Research in Texas. "We did show the rates of chemotherapy and radiation therapy are less in the older group."

Jones and his colleagues tracked nearly 10,000 women who had already gone through menopause and who had been diagnosed with hormone receptor-positive breast cancer.

That is the most common type of the disease, and it is considered less dangerous than the hormone receptor-negative types because it is often slower growing and might respond to hormone treatments.

Younger women are more likely than older women to have the receptor-negative cancer and they also tend to get diagnosed at a later stage, leading to the idea that breast cancer is more deadly for them.

In this study, the researchers found that five out of every 100 women who were diagnosed under age 65 and six out of every 100 women diagnosed between 65 and 74 years old died from breast cancer within five years.

Among women over age 75 at the time of their diagnosis, eight out of every 100 died from the cancer.

The team isn't sure how to account for the gap, but Dr. Hyman Muss of the University of North Carolina School of Medicine, agreed with Jones.

"What's different in older women is they tend to get lesser and poorer treatment," said Muss, who was not involved in the new study.

About one in eight American women will get breast cancer at some point in their life, but less than a fourth of them will die from it.

Breast cancer can be treated with a combination of surgery, radiation, chemotherapy and hormonal medications.

Nearly all the women in the study went through surgery, but just half of the women over age 75 had radiation, and just five percent had chemotherapy.

In comparison, 75 percent of women under age 65 received radiation and 51 percent had chemotherapy.

"There are beliefs that older women do not benefit from chemotherapy as much as younger women, and that the side effects are worse," said Dr. Gerrit-Jan Liefers, a researcher at Leiden University Medical Centre in The Netherlands who also worked on the study.

He added that the patients themselves may also be more hesitant to treat their cancer aggressively.

A recent study found that, while the rates of breast cancer deaths have been slowing, older women have had smaller gains than younger women (see Reuters Health report of November 11, 2011).

Those authors also attribute the differences in part to less aggressive treatment in older women.

"You don't want to treat older women so aggressively that you actually cause more problems from the treatment than from the disease," Dr. Benjamin Smith from the University of Texas MD Anderson Cancer Center in Houston, who worked on that study, told Reuters Health in November.

Muss said it's possible to overtreat elderly patients, but otherwise healthy women in their 70s would likely benefit from chemotherapy.

"We need to teach doctors not to think of a person's chronologic age, but think of their functional age," Muss said.

Liefers said clinicians badly need a tool that can help them better calculate the optimal treatment for older women.

His findings, published in the Journal of the American Medical Association, also showed that as women got older, the chances of dying from something other than their breast cancer increased dramatically.

The encouraging finding for women of all age groups is that the vast majority will survive their cancer, Jones pointed out.

"The overall death rates are pretty low," he told Reuters Health. "I think that's a good message."

SOURCE: http://bit.ly/4HWZ7 Journal of the American Medical Association, February 8, 2012.

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