The British Columbia Mammography Screening Program: evaluation of the first 15 months

We report our experiences in the first 15 months of a government-funded pilot project begun in 1988 to study the feasibility of rapid throughput, low-cost screening mammography in British Columbia. The primary goals of the project were (1) to determine the unit cost of screening mammography within the context of the program; (2) to design and put into operation a centralized system of data collection, analysis, and quality control to enable calculations of cancer detection rates, biopsy rates, biopsy yield ratios, staging, and other specific cancer characteristics; and (3) to study compliance in the community where the program was offered. A total of 11,824 women had mammography at a unit cost of U.S. $32.66. Computerized analysis revealed that (1) 11% of women had known primary risk factors; (2) findings on mammograms were interpreted as abnormal in 9% of screening examinations; (3) breast cancers were confirmed in 47 (22%) of 211 patients who had biopsies, and 87% of these were stage 0-1. The overall cancer detection rate was four per 1000, with five per 1000 for women who had not had mammography in the preceding 2 years and one per 1000 for women who had had mammography in the past 2 years. The results show that screening mammography can be conducted at low cost. Data collection and analysis and compliance were sufficiently convincing to initiate province-wide expansion.