It’s a tough call, deciding which topics gets readers most incensed. Evolution always makes a strong run for the title, but I have to go with something else: readers get really, really upset when you tell them that early cancer detection is unlikely to save their life.

So apologies that I have to say it again. But the latest review of studies evaluating the value of monthly breast self-exams—a staple of college health centers, OB-GYN visits and women’s mags—comes to a dismal conclusion: there is no evidence that they actually reduce breast-cancer deaths, and instead may do more harm than good.

Before you roll your eyes and say, oh, just one little study, what does it know?, let me say this: there are actually a lot of studies casting doubt on what breast self-exams can do for you. In 2002, for instance, scientists at the Fred Hutchinson Cancer Research Center in Seattle concluded in the Journal of the National Cancer Institute that teaching women breast self-examination does not decrease the number of deaths in the group from breast cancer. And just as the study released this evening finds, teaching BSE increases the rate of benign breast biopsies, which are no fun. A JNCI editorial concluded that rather than spending time teaching breast self-exam, physicians should educate women about cancer symptoms and take more time performing the clinical breast exam. “Routinely teaching BSE may be dead,” they wrote, “but giving women information . . . should live on.”

Alas, six years later, BSE is not at all dead, and the myth of the value of self-exam persists. Lest you think this is all a vast conspiracy on the part of unfeeling male scientists to make more of us die from breast cancer, check out the Website of the National Breast Cancer Coalition, a women's research and advocacy group that has often taken unpopular positions. For years it has been telling women that “there is currently no scientific evidence from randomized trials that breast self-exam (BSE) saves lives or enables women to detect breast cancer at earlier stages. In addition, there are some data that show that BSE greatly increases the number of benign lumps detected, resulting in increased anxiety, physician visits, and unnecessary biopsies. Therefore, NBCC does not support efforts to promote and teach BSE on a population-wide level in any age group of women.” And the American Cancer Society stopped recommending monthly self-exams five years ago; there’s just no evidence it saves lives.

How can it be that self-exam doesn’t make you less likely to die of breast cancer, as the latest paper, from the Cochrane Library, concludes? (And that the PSA test for prostate cancer, mammograms, and X-ray screening for lung cancer also have little to no value in keeping you alive?)

For one thing, many tumors grow so slowly that they can be in you for years with no ill effects. So whether you find the tumor today or on July 15, 2014, makes no difference. For another, just because someone who found a tumor herself lives for 17 years, while someone whose tumor was found on a mammogram lived only 6, doesn’t mean the earlier detection improved survival: the ultimately fatal outcome might have been inevitable, and the only thing early detection bought was more years of living with cancer, not more years of life.