AS USEFUL AS SCREENS ON A SUBMARINE:

Cancer Screening May Do More Harm Than Good (SHANNON BROWNLEE, Mar 15, 2009, NBC)

It's hard to believe, but some researchers wouldn't call Bull lucky at all. They say that yearly mammograms are not nearly as effective at reducing the risk of dying of breast cancer as most women think, and that mammography leads many women to get unnecessary treatment -- especially those diagnosed with DCIS. The problem is bigger than just mammography: They say the prostate-specific antigen (PSA) test may do men more harm than good if they don't already have symptoms of prostate cancer. And they have similarly grim things to say about other widely used cancer screening tests.

Their view stands in stark contrast to the message being put out by groups like the American Cancer Society and even the federal government, which say that finding and treating tumors as early as possible is the surest way to avoid a cancer death. But a growing group of scientific heretics -- published in highly respected medical journals, working at some of the most august institutions -- strongly believe that it's time to rethink our whole approach to cancer screening.

That's because screening tests pick up many small cancers that would never have caused any symptoms. "Screening for cancer means that tens of thousands of patients who never would have become sick are diagnosed with this disease," says H. Gilbert Welch, MD, codirector of the Outcomes Group at the Veterans Affairs Medical Center in White River Junction, Vermont, and a leading expert in cancer screening. "Once they're diagnosed, almost everybody gets treated -- and we know that treatment can cause harm." Tamoxifen for breast cancer can trigger life-threatening clots in the lungs, for instance. Surgery for prostate cancer leaves 60 percent of men unable to have an erection. For that matter, some of the screening tests themselves carry risks: Up to 5 out of every 1,000 people who get a colonoscopy have a serious complication, such as a colon perforation or major bleeding.

Most people diagnosed with cancer undoubtedly see these risks as the price they must pay to avoid dying of cancer. "The reality is not so simple," says Dr. Welch. Screening tests are very good at catching tumors that would never bother us, he notes, but they're actually pretty bad at catching the fastest-growing and most deadly cancers in time to cure them. The bottom line, says researcher Floyd Fowler, Jr., PhD, president of the Boston-based nonprofit Foundation for Informed Medical Decision Making: "Screening's power to cut your risk of dying has been wildly overinflated."