In situ ductal carcinoma of the breast: implications of disease pattern and treatment.

Ninety-seven patients with in situ ductal carcinoma (DCIS) of the breast have been reviewed. The commonest presenting feature was a breast lump, and residual carcinoma was found in the mastectomy specimen in 63% of patients. Furthermore, 13 cases had evidence of infiltrating carcinoma when the mastectomy specimen was examined. Thus excision alone would have left residual in situ or infiltrating carcinoma in two-thirds of the cases. A wide excision, by removing local residual disease, would still have left multifocal disease in one-third of cases. Studies need to be conducted to determine whether conservative treatment of DCIS can yield results which are as good as those following total mastectomy.