Does increased detection account for the rising incidence of breast cancer?

Background: The incidence of breast cancer has been increasing over time in the United States. Methods: To determine the role of screening in this increase, trends in the incidence of in situ and invasive carcinoma of the breast were evaluated using records of the metropolitan Atlanta SEER program between 1979 and 1986. From a sample of records, evidence of symptoms and mammographic screening prior to diagnosis was recorded. Results: The average annual age-adjusted incidence of invasive disease rose 29 percent among Whites and 41 percent among Blacks. Incidence increased in all age groups. A trend towards earlier detection of invasive disease was found. Asymptomatic tumors accounted for only 40 percent of the increased incidence among whites and 25 percent of the increased incidence among blacks, with mammography as the principal contributing procedure. Conclusions: These data suggest that increased detection accounts for some but not all of the rising incidence of breast cancer in the United States.