Mammographic accuracy and patient age: A study of 297 patients undergoing breast biopsy

Abstract

This study was undertaken to compare the diagnostic accuracy of mammography in patients under 50 years with that of patients over 50, and with further subdivisions under 35 and 65 years. A retrospective review of the mammograms of 297 sequential patients undergoing mammography prior to surgical breast biopsy at the Breast Unit, Royal Marsden Hospital, London from 1988-1991 was performed. The films were reviewed blind by a single radiologist and correlated with histological findings at biopsy. The sensitivity and specificity of mammography compared with histology in four age-groups was assessed. There were 144 patients in the under-50 age group (< 35 years = 20, 35-49 years = 124), and 153 patients aged over 50 (50-64 years = 96, > 65 years = 57). Of all patients with histologically malignant biopsies 79% of the under-50s and 76% of the over-50s were diagnosed mammographically. Sensitivity of mammography was therefore 3% greater in the under-50 age-group (95% confidence interval (CI): +16% to -10%). Of patients who had benign biopsies, 76% of the under-50s and 75% of the over-50s were correctly diagnosed by mammography. Mammographic specificity was therefore 1% greater in the over-50 age-group (95% confidence interval: +15% to -14%). Accuracy of mammography was also comparable in the four subdivided age-groups. The results suggest that in patients requiring breast biopsy, contemporary mammography is similar in accuracy in the younger patient when compared to the older post-menopausal patient.