Correlation between imaging and pathology in ductal carcinoma in situ of the breast

BACKGROUND It is helpful in planning treatment for patients with ductal carcinoma in situ (DCIS) if the size and grade could be reliably predicted from the mammography. The aims of this study were to determine if the type of calcification can be best used to predict histopathological grade from the mammograms, to examine the association of mammographic appearance of DCIS with grade and to assess the correlation between mammographic size and pathological size. METHODS Mammographic films and pathological slides of 115 patients treated for DCIS between 1986 and 2000 were reviewed and reclassified by a single radiologist and a single pathologist respectively. Prediction models for the European Pathologist Working Group (EPWG) and Van Nuys classifications were generated by ordinal regression. The association between mammographic appearance and grade was tested with the chi2-test. Relation of mammographic size with pathological size was established using linear regression. The relation was expressed by the correlation coefficient (r). RESULTS The EPWG classification was correctly predicted in 68%, and the Van Nuys classification in 70% if DCIS was presented as microcalcifications. High grade was associated with presence of linear calcifications (p < 0.001). Association between mammograhic- and pathological size was better for DCIS presented as microcalcifications (r = 0.89, p < 0.001) than for DCIS presented as a density (r = 0.77, p < 0.001). CONCLUSIONS Prediction of histopathological grade of DCIS presenting as microcalcifications is comparable using the Van Nuys and EPWG classification. There is no strict association of mammographic appearance with histopathological grade. There is a better linear relation between mammographic- and pathological size of DCIS presented as microcalcifications than as a density, although both relations are statistically significant.