Radiographic screening for breast carcinoma. III. Appearance of carcinoma and number of projections to be used at screening.

The films of 117 patients with mammary carcinoma detected at population screening were reviewed. Sixteen per cent (19) of the women proved to have non-invasive and 43 per cent (50) small invasive carcinomas (diameter less than or equal to 10 mm). Calcifications were the dominating abnormality in 95 per cent of the non-invasive carcinomas, while a tumour mass was the most frequent abnormality in small invasive carcinomas. It was found that the appearance of small tumours may vary considerably from one projection to another and also on films in one and the same projection. Thus, approximately 20 per cent of small invasive carcinomas were either not visible or equivocal in one of the two projections used at screening. The corresponding figure for larger invasive carcinomas (diameter greater than 10 mm) was approximately 7 per cent. It is concluded that films in two projections, preferably the craniocaudal and oblique, should be obtained at screening.