A Co-Operative Evaluation of Mammography in Seven Teaching Hospitals

Abstract

In a study including 2,022 patients and the results of breast biopsies in 776, mammographic diagnoses were compared to histopathologic diagnoses, and an accuracy (true-positive rate) of 68 percent was found in cancer detection. This was increased to 80 percent in women over 55, in those with fatty breasts, and in those with clinically obvious carcinoma. The accuracy was 50 percent in patients in whom cancer was not clinically obvious. A yield of 6 unsuspected carcinomas/5, 000 patients was found when breast patients with no dominant mass were subjected to routine mammography. Excluding clinically obvious carcinoma, 50 percent of patients with a mammographic diagnosis of cancer were found to have a malignant lesion at operation, indicating that mammographic diagnosis of cancer is an indication for biopsy. Mammography cannot be relied upon to exclude carcinoma in women under 55 years but will aid in the diagnosis of a few early carcinomas which might otherwise be missed.