Effect of Screening Mammography on Breast Cancer Incidence
To the Editor: As Bleyer and Welch report (Nov. 22 issue),1 screening mammography has had a limited effect on breast cancer mortality in the United States; over the course of 30 years, age-adjusted incidence rates of late-stage cancers have decreased by only 8%, and no significant change is noticeable in the incidence rates of cancers diagnosed after they have metastasized to distant organs. Similar studies in the United Kingdom, the Netherlands, Italy, Switzerland, Norway, and Australia have shown limited decreases, if any, in the incidence of advanced breast cancers after 15 to 20 years of widespread screening.2?4 Hence, it . . .