Mammography Under the Gun

By Dr. Ralph Moss
from CancerDecisions.com Newsletter

The cancer world has been shaken by a debate over the merits of screening mammography for breast cancer. Drs. Peter C. Goetzsche and Ole Olsen of the Nordic Cochrane Collaboration in Copenhagen reviewed all the clinical trials for mammography. They concluded, in the medical journal, the Lancet, that "there is no reliable evidence that screening for breast cancer reduces mortality." In late January, 2002, a branch of the US National Cancer Institute agreed with them that the "evidence justifying mammography was shaky."

The Cochrane Collaboration, the Lancet and the NCI are bastions of orthodox medicine. Because of this, even the New York Times joined in the attack (January 27, 2002). In a lead editorial, "Uncertainty Over Mammograms," the Times questioned the likelihood of ever getting an honest answer to the question of whether or not mammography is a worthwhile screening technique.

"It may not be easy to get a truly independent review," they wrote. "Mammography has been so strongly endorsed by the cancer establishment and has become such a significant source of revenue and patients for many hospitals and doctors that it may be difficult to excise without overwhelming evidence that it is dangerous." (Dangerous? This is odd, since the Cochrane researchers did not say that mammography is dangerous, only that it is ineffective.)

How amazing to hear the Times speak of "the cancer establishment." And that establishment was not slow in responding. Four days later, ten US medical groups, including the American Cancer Society and the American Medical Association, placed a full-page ad in the New York Times, supporting mammography. The ad coincided with an article by Claudia Henschke, MD, of Cornell Medical Center, also published in the Lancet, which analyzed one 1988 clinical trial from Malmoe, Sweden. She concluded that mammography did, indeed, reduce deaths.

How could these researchers be so far apart in analysis of the same studies? Because Goetzsche and Olsen looked at all the people who had died of any causes, while Henschke looked only at people who had specifically died of breast cancer in one study, and ignored all other causes of death. This is comparing apples and oranges. Overall survival is a more meaningful outcome than disease-specific survival. The reason is that the treatments themselves may cause deaths. (Even Henschke concedes that early detection and treatment may be associated with "somewhat increased mortality" in earlier years). By failing to take account of all causes of death one conveys an unduly positive estimate of the intervention.

Expect to see an escalating campaign to counteract the negative findings. The establishment will pull out all of the stops on this one, because mammography is the centerpiece of the whole orthodox strategy on breast cancer. On the ABC Evening News, I heard a prominent doctor from Memorial Sloan-Kettering sternly warn that women would die if they listened to Goetzsche and Olsen's arguments. Dr. Tim Johnson, the network's resident MD, strongly urged women to continue getting their mammograms (2/1/02). He conveyed the impresson that even the Lancet now admits that mammography works."

Yet here is the actual opinion of the Lancet's editor-in-chief, Richard Horton, MD. "The public believes mammography to be far more effective than it really is," he said. "Women deserve an accurate assessment of the benefits or harm from screening mammography. That means encouraging an open debate about the issue."

Note from Chet: Be sure to sign up for Dr. Moss's excellent newsletter at his website.