Ductal carcinoma in situ of the breast: correlation of pathologic and mammographic features with extent of disease.

Optimal treatment of ductal carcinoma in situ (DCIS) of the breast requires an improved understanding of its pathologic extent and propensity for local recurrence. This study was performed to analyze mammographic and pathologic features of DCIS that might predict the extent of disease within the breast and facilitate treatment selection between lumpectomy alone, lumpectomy and radiotherapy, and mastectomy. At our institution, 60 cases of DCIS were diagnosed in 59 patients from June 1985 to February 1995 and form the basis of this retrospective study. Demographic and treatment-related information was obtained from hospital and tumor registry records. Mammograms were reviewed and size estimates of the abnormalities were determined. Pathologic slides from all cases were reviewed and classified according to size group, focality, nuclear grade, necrosis, and histologic subtype. DNA ploidy status and proliferation indices were available for 28 patients. Pathologically, 43 (72%) cases were < 15 mm, 14 (23%) were 16 to 40 mm, and 3 (5%) were > 40 mm. Five (8%) of the lesions were multicentric, 28 (47%) focal, and 27 (45%) multifocal. Thirty-three (55%) patients were treated by mastectomy, 16 (27%) by lumpectomy alone, and 11 (18%) by lumpectomy and radiation therapy. Mammographic size, histologic grade, presence or absence of necrosis, histologic subtype, DNA ploidy, and proliferative index were compared with pathologic size and focality by chi 2 analysis. Mammographic size correlated significantly with pathologic size (chi 2 = 11.3; P = 0.02) but underestimated the extent of disease in 9 cases. Although focality correlated significantly with pathologic size (chi 2 = 15.8; P = 0.003), the remaining histopathologic features did not significantly correlate with pathologic size or focality. Histopathologic features, including DNA studies, do not reliably predict the pathologic extent of DCIS, but mammographic size and focality do significantly correlate with pathologic size. Nevertheless, most cases of DCIS are small focal or multifocal lesions that are amenable to breast conservation approaches; further studies are needed to determine the appropriate use of lumpectomy, radiation therapy, and mastectomy in the treatment of DCIS.