The significance of mammographic calcifications in early breast cancer detection

3,126 medical reports on women sent to mammary biopsy following breast examination at the Florence Center for the Study and Prevention of Cancer in November 1978-July 1982 were reviewed in order to assess the diagnostic significance of mammographic microcalcifications. All mammographies were examined in order to assess the presence and morphological aspects of the microcalcifications on the bioptic site. Microcalcifications were classified on the basis of the following morphological criteria: spatial disposition (isolated, clustered, diffuse); total number; number per cm; morphological aspect (dot-like, stick-like or ramified); shape (regular or irregular); radiological density; association with mammographic opacity; maximum and average diameter. Microcalcifications were encountered in 19.7% of 157 breast cancer diagnosed in a mammographic screening programme conducted on the asymptomatic population in 19.5% of 953 breast cancers diagnosed in self-referring women (most with symptoms). Among cases where subsequent histological examination revealed a benign pathology, microcalcifications were more frequent in the cases deriving from the screening programme (14.5% of 198 cases) than among self-referred cases (4.5% of 1818 cases). The presence of microcalcifications is in itself a predictive sign of the presence of a carcinoma (positive predictive value = 66.2%) but this radiological sign is only present in 20% of breast cancers. Among the various parameters considered in assessing the diagnostic significance of microcalcifications, irregular shape was the most indicative of carcinoma with a predictive value of 80% and presence in 88% of carcinoma with microcalcifications. Other microcalcification parameters with a particular predictive significance are diffuse spatial disposition, total number (over 10) and number per cm (over 50), site contiguous with a mammographic opacity and a mean diameter of 0.6-0.9 mm. Unfortunately these latter parameters are only 24% of tumour cases with microcalcifications. The incidence of microcalcifications in cancer does not vary according to age, but is strongly correlated with the tumour stage. In particular microcalcifications are found in about 1/3 of in situ carcinomas. In invasive cancers, the presence of microcalcifications tends to increase with the diameter of the lesion. No correlation was found in breast cancers between the presence of microcalcifications, lymph node condition and histological type.(ABSTRACT TRUNCATED AT 400 WORDS)