False-negative mammograms in patients with breast cancer

Because of reports that negative mammographic findings have resulted in a delay of treatment in patients with breast cancer, the authors reviewed their experience with mammography in 160 patients, admitted to the Sir Mortimer B. Davis-Jewish General Hospital in Montreal over a 28-month period, who had histologically verified carcinoma of the breast. Of these patients 153 had clinically palpable masses and 7 had occult carcinomas. The mammogram was considered to be positive for carcinoma in 112 (73.2%) and negative in 41 (26.8%). In 44 patients under the age of 50 years the mammogram was positive in 26 (59.1%) and negative in 18 (40.9%), a significant difference (P less than 0.05). There was no significant difference between the findings of mammograms read by the hospital radiologists and those read by community radiologists. This study confirms the findings of others that mammography is not a reliable technique for evaluating the clinically suspicious breast lesion and must not be used as a substitute for biopsy of such lesions.