Radiological findings of screen-detected cancers in a multi-centre randomized, controlled trial of mammographic screening in women from age 40 to 48 years.

AIM To elucidate the mammographic findings of screen-detected cancers in women screened between 40-48 years, and to establish the frequency and nature of abnormal findings on previous mammograms in women with screen-detected cancers. METHODS A radiology review panel consisting of three experienced breast radiologists viewed the screening mammograms in chronological order, confirming that any abnormalities detected corresponded to the cancers detected at later screens. An analysis correlating mammographic features with median invasive size and the proportion measuring less than 10 and 15mm was performed. RESULTS Two hundred and thirty-two women had screen-detected invasive cancers with mammograms available for review. The most frequent features seen at diagnosis were spiculate mass, ill-defined mass, granular calcification, deformity and comedo calcification. Thirty-four percent of mammograms showed calcification. The mammographic sign associated with smallest median size was calcification. Calcification was also the mammographic abnormality most frequently associated with cancers <10mm in size. In total there were 147 abnormal previous screens of 87 women. The most commonly missed features were granular microcalcification, deformity and ill-defined mass. Of the missed abnormalities 20% were classified as malignant, 43% as subtle change and 32% as non-specific. CONCLUSION Compared with older women, screen-detected cancer in younger women more commonly manifests as calcification and less frequently a spiculate mass. Calcification is the sign most frequently associated with invasive cancers <10mm in size. Calcification and deformity are the signs most frequently seen on the previous mammograms of women with screen-detected cancer.