The New Mexico Mammography Project. Screening mammography performance in Albuquerque, New Mexico, 1991 to 1993

This project was designed to collect and link population-based mammography and breast carcinoma data to assess the performance of community mammography screening.

Computerized data were collected from all radiology practices in Albuquerque, New Mexico. The data were linked by computer match to breast carcinomas in a statewide cancer registry. Analysis is based on 126,466 screening mammogram studies performed on 87,443 female residents of New Mexico between the ages of 35 and 84 by 5 radiology groups. Sensitivity, specificity, positive predictive value, and call back rates were calculated as indicators of the discriminative performance of mammography. Carcinoma size and stage distribution were analyzed as outcome measurements.

The computer match linked 634 breast carcinomas to the 126,466 screening mammogram series. The community-wide sensitivity was 79.9%, and specificity was 90.5%. The predictive value of an abnormal screen was 4.3%, and that of a biopsy recommendation result was 16.9%. The call back rate was 11.4%. The median invasive breast carcinoma size was 15 mm, 20.3% of carcinomas were in situ, 18.3% were lymph node positive, and 68.1% were Stage 0 or Stage 1.

Mass screening mammography as practiced in Albuquerque, New Mexico, is able to detect breast carcinomas at early, treatable stages. The stage distribution of carcinomas is similar to that seen in successful clinical trials. However, measures of mammography performance show lower sensitivity, more additional studies, and more biopsy recommendations in this community setting than have been reported by expert mammographers.