Pandora's Lab: Seven Stories of Science Gone Wrong

by Paul A. Offit

Mammography screening for breast cancer is also being reevaluated. Although it is clear that mammography, which was first introduced into the United States in the mid-1970s, saves lives; the question is how many and at what cost. In 2012, Archie Bleyer and Gilbert Welch published a study in the New England Journal of Medicine titled “Effect of Three Decades of Screening Mammography on Breast-Cancer Incidence.” They found that, with the advent of screening mammographies, the incidence of breast cancer in the United States had doubled. For every 100,000 women screened, the number of women diagnosed with breast cancer had increased from 112 to 234. In other words, every year 122 more women (per 100,000) were being diagnosed with breast cancer. At the same time, the number of women presenting with late-stage breast cancer (the kind that often results in death), decreased from 102 to 94 (per 100,000). This meant that only 8 women among 122 appeared to benefit from the screening. Eight. The others were treated with mastectomy, radiation therapy, and chemotherapy without benefit. The authors concluded that, although the incidence of death from breast cancer had clearly decreased during the era of screening mammography, most of that decrease was due to better treatment, not better screening. They also estimated that during the three decades of mammography, about 1.3 million women had been diagnosed with a cancer that would never have killed them. The authors concluded that, “scree...