Switching from a “Western” diet with lots of fat and meat to a fiber-rich diet for just two weeks makes conditions in the large intestine less favorable to the development of colon cancer. The opposite switch may promote the formation of cancer. That’s the conclusion from a small but elegant study done in urban Pittsburgh and rural KwaZulu-Natal, South Africa. In the study, 20 volunteers from each area switched diets. For two weeks, the Americans ate a traditional high-fiber African diet rich in fruits, vegetables, nuts, and beans, while the Africans ate a Western diet with more fat, protein, and meat. In just two weeks, significant changes occurred in the lining of the colon and in its chemical and bacterial make-up in both groups, but in different directions. Those following the African diet showed improvements in colon health likely to protect against colon cancer, while those following the Western diet showed changes that could lead to colon cancer.
Looking for ways to ward off colorectal cancer? According to a new study, a pescovegetarian diet — that’s a vegetarian diet that includes fish — was linked to a 43% reduction in the risk of developing colorectal cancer. The study, published in JAMA Internal Medicine, adds more support to the notion that something in red meat, or the way it is cooked, encourages the growth of colorectal cancer. It’s also possible that eating more plant foods provides extra beneficial nutrients such as folate, calcium, and fiber that may protect against colorectal cancer. Fish contain healthful omega-3 fats and vitamin D. Another good strategy for preventing harm from colorectal cancer, the second leading cause of cancer death in the United States? Have colonoscopies as needed.
Over the past decade, a barrage of reports linking low vitamin D levels to cancer, heart disease, diabetes, and a host of other ills led many doctors to routinely test vitamin D levels in their healthy patients. But there is no good reason to do that, according to a new recommendation from the U.S. Preventive Services Task Force (USPSTF) published in this week’s Annals of Internal Medicine. The task force concluded that it isn’t helpful for most people to know their vitamin D level, and that even if you have a “low” vitamin D level there’s little evidence that taking a vitamin D supplement will do most people any good.
Last spring, an advisory panel for the Center for Medicare and Medicaid Services (CMS) recommended that Medicare not cover low-dose CT scans for smokers or former smokers. These scans can double the proportion of lung cancers found at an early stage, while they are still treatable. Yesterday, CMS announced that it would cover the cost of these scans for people between the ages of 55 and 74 who smoke, or who quit within the last 15 years, and who have a smoking history of 30 pack-years. (That means a pack a day for 30 years, two packs a day for 15 years, etc.) The new Medicare plan would cover scans for an estimated 4 million older Americans, at a cost estimated to be more than $9 billion over five years. In a wise addition, Medicare will require smokers to get counseling on quitting or the importance of staying smoke-free before having the annual scan.
The best test for finding hidden lung cancer in smokers is a low-dose CT scan. Its use has been endorsed by the U.S. Preventive Services Task Force (USPSTF), an independent panel that makes recommendations for screening tests. Most insurers follow the recommendations of the task force, and pay for those services. But some opposition to this by Medicare may mean that the test isn’t covered for some of the people who could benefit from it the most. A new report in the New England Journal of Medicine showed that the cost of adding one good year to a person’s life through CT screening is around $80,000. Tests or procedures that cost less than $100,000 per year added are considered cost effective. The analysis identified two groups for whom screening is the most cost-effective—current smokers and people ages 60-74. People with private insurance will have low-dose CT scans covered. But those with Medicare may not, thanks to the decision of a Medicare advisory committee. The CMS is expected to publish a draft of its decision within the next few days and come to a final decision in early 2015.
According to one persistent Internet myth, women who wear bras are more likely to develop breast cancer. Not true, says a study published online in the journal Cancer, Epidemiology, Biomarkers, and Prevention. In a study of more than 1,500 women, researchers from the Fred Hutchinson Cancer Research Center in Seattle found no links between risk of two common types of breast cancer — invasive ductal carcinoma or invasive lobular carcinoma — and any aspect of bra wearing, including cup size, use of a bra with an underwire, age at first bra use, and average number of hours per day a bra was worn. This may not be the last word on the subject, since the Fred Hutchinson study represents only the second to look at the connection between bra use and breast cancer. But until other findings appear, women worried that wearing a bra might cause cancer have one less thing to worry about.
Screening — checking a seemingly healthy person for signs of hidden disease — is an important part of routine medical care. It is done for various types of cancer, heart disease, diabetes, and other chronic conditions. Screening makes sense when finding and treating a hidden condition will prevent premature death or burdensome symptoms. But it doesn’t make sense when it can’t do either. That’s why experts recommend stopping screening in older individuals, especially those who aren’t likely to live another five or 10 years. Yet an article published online in JAMA Internal Medicine shows that many doctors still recommend cancer screening tests for their older patients. Many don’t benefit, and some are even harmed by the practice. Asking people who can’t benefit from a cancer screening test to have one is a waste of their time and money, not to mention a waste of taxpayer money (since these tests are usually covered by Medicare). Screening tests can also cause physical and mental harm. Decisions about cancer screening should be mutually made by an individual and his or her doctor. Equally important, the person should be well informed about the risks of the test and about what will happen if a test suggests there may be cancer that won’t shorten the his or her life.
A study published in JAMA Internal Medicine this week found that men who used the erection-enhancing drug sildenafil (Viagra) were 84% more likely to develop melanoma, the most dangerous form of skin cancer, over a period of 10 years. That finding makes for an attention-grabbing headline. But it doesn’t tell the real story—that the study found an association (not cause and effect), that this hasn’t been seen in other studies of men, and that, even if it holds true, the absolute increase is small, from 4.3 cases of melanoma for every 1,000 men who didn’t take Viagra to 8.6 of every 1,000 men who took it. The take-home message is that it’s important to worry about melanoma—which is largely caused by getting too much sun—but not yet about Viagra and melanoma.
Some good news on the cancer front: between 2000 and 2010, rates of colorectal cancer in American adults fell by about one-third. That decline mirrored a sharp rise in colorectal cancer testing during the same period. American Cancer Society researchers found that the drop in colorectal cancer rates was highest among Americans aged 65 years and older. Cases fell 3.6% a year from 2001 to 2008, then dropped even more by 7.2% a year from 2008 to 2010. But the researchers saw a troubling trend in younger adults: an increase in colorectal cancer of 1.1% a year among people under age 50. Rising obesity rates may be to blame. The researchers attribute the decline in colorectal cancer to early testing for the disease. Despite the optimistic findings, colorectal cancer is still a scourge. In the U.S. this year, an estimated 72,000 men and 65,000 women will be diagnosed with colorectal cancer; 26,000 men and 24,000 women will die of it.
Mass marketing of testosterone therapy may have men eager to try this seemingly simple fix. But the latest science should have them scratching their heads and putting away the credit card—at least for now. A new study published in the online journal PLOS One shows an increase in the risk of having a heart attack in the months after starting testosterone therapy. The potential for danger was highest in older men. A report in the November 6, 2013, issue of JAMA showed that men who used testosterone therapy didn’t fare as well after artery-opening angioplasty as men who didn’t take testosterone. Neither was the type of study that can prove cause and effect. They can only show associations, or links. That means there’s no smoking gun here that testosterone therapy is harmful. But the studies do suggest caution. Given the uncertainly over the benefits and risks of testosterone therapy, what’s a man to do? Take a cautious approach, advises the Harvard Men’s Health Watch.