Overdoing breast cancer detection?

Here s another instance where the headlines may be true, but the impact on most women will be next to nothing. Study finds some early breast cancer overdiagnosed, reads a recent AP headline. It refers to a new study from Norway that estimates that 15 to 25 percent of breast cancers detected by mammograms would not have caused any problems during a woman s lifetime if left alone. The concern is that these tumors were treated anyway either by surgery or with radiation or chemotherapy. Even more perplexing, the tumors discovered were all found to be of the invasive pathology, not the local lesions called in situ. The study is the latest in a number that have investigated the problem of overdiagnosis that accompanies routine mammograms. However, the dilemma is that there is no way to tell which early tumors will actually become problematic.

The researchers, whose study appears in the Annals of Internal Medicine, analyzed nearly 40,000 breast cancer cases among women in Norway, including close to 8,000 that were detected after routine screening began. According to their findings, they estimated that, for every 2,500 women offered screening, one death from breast cancer will be prevented but six to 10 women will be treated who do not actually require treatment. Thus, these women can be said to have been overdiagnosed a concept that only applies in retrospect, however.

Still, doctors are not yet sure how to make practical use of this information. As one of the researchers observed, "Once you've decided to undergo mammography screening, you also have to deal with the consequences that you might be overdiagnosed. By then, I think, it's too late. You have to get treated."

Both ACSH's Dr. Elizabeth Whelan and Dr. Gilbert Ross agree with this observation. Once you ve detected a tumor in a woman s breast, it s very difficult to tell her that she should watch and wait, says Dr. Whelan.

Nevertheless, for now, the researchers feel that they have an ethical responsibility to alert women to this phenomenon. What repercussions it may have are yet to be determined.