|
Lifestyle Changes May Reduce Cancer Risk
Simple lifestyle measures may reduce the risk of recurrence of certain types of cancer, according to researchers reporting at the recent American Society of Clinical Oncologists annual meeting.
For the first time, evidence suggests that reducing dietary fat can reduce the risk of breast cancer recurrence in postmenopausal women.
According to the American Cancer Society (ACS), the chance of developing invasive breast cancer at some time in a woman’s life is about 1 in 7 (13.4 percent). It is estimated that in 2005 about 211,240 new cases of invasive breast cancer will be diagnosed among women in the US. At this time there are slightly over 2 million women living in the US who have been diagnosed with and treated for breast cancer.
And another study found that regular aspirin use may reduce the risk of colon cancer recurrence.
Excluding skin cancers, colorectal cancer is the third most common cancer diagnosed in men and in women in the US. The ACS estimates that about 104,950 new cases of colon cancer (48,290 men and 56,660 women) and 40,340 new cases of rectal cancer (25,530 men and 16,810 women) will be diagnosed in 2005.
Women in the breast cancer study who followed a low-fat diet experienced a 24 percent improvement in relapse-free survival, compared with women in a control group who did not lower their fat intake.
"It's a demonstration that intervention programs that are resulting in lifestyle changes can be successful," says Dr. Robert Morgan, Jr., a staff physician in medical oncology and therapeutics research at City of Hope Cancer Center, in Duarte, Calif.
"A lot of doctors have been quite pessimistic in our ability to effect lifestyle changes in patient populations," Dr. Morgan says. "These statistics are compelling and hypothesis-generating, although they clearly need a follow-up study."
Study author Dr. Rowan T. Chlebowski, a medical oncologist at Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, says "The role of dietary fat in breast cancer was raised about a quarter of a century ago, first by country differences in [breast cancer] incidence and in outcome after diagnosis.
"But over the past 25 years, the precise role of dietary fat intake in breast cancer recurrence has remained an open question," he says.
To address this open question, Dr. Chlebowski and his colleagues conducted a randomized, prospective trial involving several centers and 2,437 women aged 48 to 79, all diagnosed with early-stage breast cancer.
All the participants had undergone surgery and, if indicated, radiation, chemotherapy, and/or tamoxifen therapy.
Within one year of diagnosis participants were randomized either to a low-fat diet or to a control group. Women in the dietary group also attended regular sessions with a nutritionist.
Although the eating plan was not designed for weight loss, women in the intervention arm lost an average of four pounds each, the researchers note.
The low-fat diet averaged 33.3 grams of fat daily - a reduction of 50 percent from the standard diet, which averaged 51.3 grams of fat per day.
After about five years of follow-up, 9.8 percent of the women on the low-fat diet had had a recurrence compared with 12.4 percent of those on the standard diet.
"There was a statistically significant difference in risk of about 3 percent at five years," Dr. Chlebowski explains.
Even more striking were the results in women with estrogen receptor-negative cancer, who had a 42 percent lower risk of recurrence compared with women on a standard diet.
"We had thought women with estrogen receptor-positive tumors would most benefit, with dietary fat influencing estrogen levels," Dr. Chlebowski notes. "But the estrogen receptor-negative group had an 8 percent absolute difference."
The researchers plan to conduct more trials to try to confirm the findings.
A second study found that stage III colon cancer patients who used aspirin regularly after their surgery reduced their risk of a recurrence and death by about 50 percent compared with nonusers.
"Regular aspirin use has been associated with a reduced risk of developing colorectal cancer and polyps," says study co-author Dr. Jeffrey Meyerhardt, a gastrointestinal oncologist at Dana-Farber Cancer Institute in Boston.
"The influence of aspirin use on the outcomes of patients with established colon cancer remains uncertain," Dr. Meyerhardt says.
This clinical trial looked at 830 stage III colon cancer patients who had undergone surgery and were getting chemotherapy. Each participant completed two questionnaires on diet, lifestyle, and medication use, one after two months of chemotherapy and one six months after chemotherapy had ended.
Almost 9 percent of the total participants described themselves as consistent aspirin users (most of them taking 81 milligrams to 325 milligrams per day).
After a median of 2.4 years of follow-up, this group had a 55 percent reduced risk of a recurrence and a 48 percent reduced risk of death.
Consistent users of Celebrex and Vioxx had similar risk reductions, but the overall numbers were smaller so this did not reach statistical significance. No benefit was seen with regular acetaminophen use.
Again, the findings require more confirmatory studies, experts state.
Always consult your physician for more information.
|
The millions of women with faux hair color can breathe a sigh of relief: New research reported in the Journal of the American Medical Association suggests that hair dye does not appear to increase the risk of cancer.
At the same time, the study authors caution that this may not the final word on the subject - more research may be needed on a tiny link seen between hair dyes and cancers such as leukemia and multiple myeloma.
"Our study is just the best summary of current scientific knowledge on the topic," says study author Dr. Bahi Takkouche, a preventive medicine professor at the University of Santiago de Compostela.
"One can never rule out that, in the future, several individual studies will find strong harmful effects. Still, the news is quite reassuring for hair dye users," he says.
Dr. Robert Morgan, Jr., section head of medical gynecologic oncology at City of Hope Cancer Center in Duarte, Calif., says, "The data should give reassurance to people that the risks of modern hair dye usage as a predisposition to cancer are, at most, very minimal."
Previous studies had suggested that hair dye might be a risk factor for several different types of cancer, including bladder cancer. Researchers had speculated that compounds called aromatic amines, which are contained in the dyes, might be responsible for the association.
According to the authors of the current study, about one third of women in Europe and North America color their hair, as do about 10 percent of men over the age of 40. The majority (about 70 percent) use permanent dyes.
The researchers analyzed data from 79 studies performed in 11 countries. Overall, they found no increased risk of breast and bladder cancer in people who used hair dye.
"Epidemiologic studies are very difficult to perform and have previously implicated many potential sources of increased risks of these cancers without any definitive conclusions," Morgan adds.
"These studies are primarily hypothesis-generating and allow scientists to focus research on potential cancer-causing agents," he says.
In addition to looking at male users of hair dye, Dr. Takkouche says that future research should be focused on the possible cancer-promoting effects of occupational exposure to hair dyes, such as that encountered by hair dressers and cosmetologists.
Here, the exposure is higher and more prolonged than with personal use, Dr. Takkouche notes.
Always consult your physician for more information.
|
