Preventing cancer is obviously the easiest—and preferable—way to save lives. So researchers are preaching what we know to do and investigating what we don't. Carel Stith is doing his part: The 63-year-old Houston lawyer is participating in a trial at M.D. Anderson Cancer Center he hopes will tell him whether, as some research has hinted, taking selenium and vitamin E supplements can stave off prostate cancer. He heard about the trial from a neighbor. "Right before that, my oldest son's godfather found out he had prostate cancer," he says. "Two weeks later, my ex-brother-in-law was diagnosed. I thought, gee, I should know a little more about this."
Vitamins and minerals are one avenue of research; in addition to the possible influence of vitamin E and selenium (for reasons unknown), there's a mounting pile of studies associating increased intake of vitamin D with a lower risk of cancer, perhaps because it plays a role in controlling the expression of genes regulating cell division. More research is needed before vitamin D is recommended specifically for cancer prevention, but some researchers say that because of its potential to prevent other conditions, a target of 2,000 IUs a day is reasonable.
Looking for clues. Beyond nutrients, recent focus has turned toward obesity and lack of exercise as culprits. Anne McTiernan, a cancer prevention researcher at Fred Hutchinson Cancer Research Center in Seattle, is trying to identify the mechanisms that might make the obese and inactive more susceptible. Perhaps the bodywide inflammation that is elevated in the obese, for example, encourages the cancer to grow. If the mechanism is known, it would be easier to figure out whether exercising and losing weight lower risk and, if so, the proper dose of each, she says. "If someone weighs 200 pounds now, we don't know if he or she should lose 50 pounds or 10 pounds. If they're inactive, we don't know if they should exercise for 30 minutes a day or an hour." Based on available research, the government recently recommended a weekly 150 minutes of moderate or 75 minutes of vigorous aerobic exercise, plus strength training, to help prevent diseases.
While links between household products and other environmental contaminants have been tough to tease out and neglected in research, that may be changing; environmental oncology is an increasingly vibrant field. Recently, bisphenol A, a compound found in certain hard, clear plastics, has raised widespread concerns that it may be associated with a higher risk of breast and prostate cancer. (A number of BPA-free baby bottles and other storage containers are now on the market.)
One thing is for sure: The single best evasive action is to quit smoking. The World Health Organization estimates tobacco use is responsible for 30 percent of cancer deaths in the developed world—mostly from lung but also from cancers of the head and neck, pancreas, and other organs. A pill that could save nearly a third of patients' lives would be the greatest success the field has ever seen.