Study: Vitamin C or E pills do not prevent cancer
MILWAUKEE — Vitamin C or E pills do not help prevent cancer in men, according to the same big study that earlier this month found these supplements ineffective for warding off heart disease.
The public has been whipsawed by good and bad news about vitamins, much of it from test-tube or animal studies and hyped manufacturer claims. Even when researchers compare people’s diets and find that a vitamin seems to help, the benefit may not translate when that nutrient is obtained a different way, such as a pill.
“Antioxidants, which include vitamin C and vitamin E, have been shown as a group to have potential benefit,” but have not been tested individually for a long enough time to know, said Howard Sesso of Harvard-affiliated Brigham and Women’s Hospital in Boston.
The Physicians Health Study, which he helped lead, was designed to do that. It involved 14,641 male doctors, 50 or older, including 1,274 who had cancer when or before the study started in 1997. They were included so scientists could see whether the vitamins could prevent a second cancer.
Participants were put into four groups and given vitamin E, vitamin C, both or dummy pills. The dose of E was 400 international units every other day; C was 500 milligrams daily.
After an average of eight years, there were 1,929 cases of cancer, including 1,013 cases of prostate cancer, which many had hoped vitamin E would prevent.
However, rates of prostate cancer and of total cancer were similar among all four groups.
The study was funded by the National Institutes of Health and several vitamin makers. Results were reported Sunday at an American Association for Cancer Research conference in Washington.
“Well-conducted clinical trials such as this are rapidly closing the door on the hope that common vitamin supplements may protect against cancer,” said Marji McCullough, nutrition chief at the American Cancer Society. “It’s still possible that some benefit exists for subgroups that couldn’t be measured, but the overall results are certainly discouraging.
“The American Cancer Society recommends getting these and other nutrients by eating a mostly plant-based diet with a variety of vegetables, fruits and whole grains. A bonus is that this type of diet helps to prevent obesity, which increases the risk of several cancers.”
About 12 percent of Americans take supplements of C and E. The new study does not mean these vitamins have no value, just that they didn’t prevent cancer in this group of doctors, who may be healthier than the general population, said Dr. Peter Shields, deputy director of Georgetown University’s Lombardi Comprehensive Cancer Center.
The best bet, Shields said, is to do things that are known to prevent the disease — eat right, maintain a healthy weight, and exercise.
Family history can trump breast cancer gene test
WASHINGTON — If breast cancer runs in the family, women can be at high risk even if they test free of the disease’s most common gene mutations, sobering new research shows.
The genes BRCA1 and BRCA2 are linked with particularly aggressive hereditary breast cancer, and an increased risk of ovarian cancer, too. When a breast cancer patient is found to carry one of those gene mutations, her relatives tend to breathe a sigh of relief if they test gene-free.
But those headline-grabbing genes account for only about 15 percent of all breast cancer cases. Even in families riddled with breast cancer, a BRCA gene is the culprit only in roughly one family of every five that gets tested, said University of Toronto cancer specialist Dr. Steven Narod.
Clearly, members of those families remain at risk from other yet-to-be-found genes. But how much risk?
Narod tracked nearly 1,500 women from 365 breast cancer-prone families, who tested negative for BRCA1 and BRCA2 mutations.
After five years, those women had a fourfold higher risk than average women of developing breast cancer, Narod reported Monday at a meeting of the American Association for Cancer Research.
This is crucial information for women considering gene testing, said Georgetown University genetics counselor Beth Peshkin, who wasn’t part of the study.
“This is contrary to what I think the common perception is,” Peshkin said. “Unless a mutation is identified in the family, a negative test result doesn’t provide reassurance.”
The good news: Narod’s study showed these women didn’t have an increased risk of ovarian cancer, like BRCA1- and BRCA2-carriers do.
While the $3,000 BRCA tests are well-accepted, newer tests for other genes linked to breast cancer are coming on the market.
But “the family history is a much stronger predictor,” stressed Narod. He recommends that such women take the anti-cancer drug tamoxifen and undergo MRI cancer checkups instead of easier mammograms “regardless of what other gene tests showed.”