What the Dog Saw [91]
The answer is that mammograms do not have to be infallible to save lives. A modest estimate of mammography’s benefit is that it reduces the risk of dying from breast cancer by about 10 percent — which works out, for the average woman in her fifties, to be about three extra days of life, or, to put it another way, a health benefit on a par with wearing a helmet on a ten-hour bicycle trip. That is not a trivial benefit. Multiplied across the millions of adult women in the United States, it amounts to thousands of lives saved every year, and, in combination with a medical regimen that includes radiation, surgery, and new and promising drugs, it has helped brighten the prognosis for women with breast cancer. Mammography isn’t as good as we’d like it to be. But we are still better off than we would be without it.
“There is increasingly an understanding among those of us who do this a lot that our efforts to sell mammography may have been overvigorous,” Dershaw said, “and that although we didn’t intend to, the perception may have been that mammography accomplishes even more than it does.” He was looking, as he spoke, at the mammogram of the woman whose tumor would have been invisible had it been a few centimeters to the right. Did looking at an X-ray like that make him nervous? Dershaw shook his head. “You have to respect the limitations of the technology,” he said. “My job with the mammogram isn’t to find what I can’t find with a mammogram. It’s to find what I can find with a mammogram. If I’m not going to accept that, then I shouldn’t be reading mammograms.”
7.
In February of 2002, just before the start of the Iraq war, Secretary of State Colin Powell went before the United Nations to declare that Iraq was in defiance of international law. He presented transcripts of telephone conversations between senior Iraqi military officials, purportedly discussing attempts to conceal weapons of mass destruction. He told of eyewitness accounts of mobile biological-weapons facilities. And, most persuasive, he presented a series of images — carefully annotated, high-resolution satellite photographs of what he said was the Taji Iraqi chemical-munitions facility.
“Let me say a word about satellite images before I show a couple,” Powell began. “The photos that I am about to show you are sometimes hard for the average person to interpret, hard for me. The painstaking work of photo analysis takes experts with years and years of experience, poring for hours and hours over light tables. But as I show you these images, I will try to capture and explain what they mean, what they indicate, to our imagery specialists.” The first photograph was dated November 10, 2002, just three months earlier, and years after the Iraqis were supposed to have rid themselves of all weapons of mass destruction. “Let me give you a closer look,” Powell said as he flipped to a closeup of the first photograph. It showed a rectangular building, with a vehicle parked next to it. “Look at the image on the left. On the left is a closeup of one of the four chemical bunkers. The two arrows indicate the presence of sure signs that the bunkers are storing chemical munitions. The arrow at the top that says ‘Security’ points to a facility that is a signature item for this kind of bunker. Inside that facility are special guards and special equipment to monitor any leakage that might come out of the bunker.” Then he moved to the vehicle next to the building. It was, he said, another signature item. “It’s a decontamination vehicle in case