The relation between the presence and extent of lobular carcinoma in situ and the risk of local recurrence for patients with infiltrating carcinoma of the breast treated with conservative surgery and radiation therapy

BACKGROUND. When found in an otherwise benign biopsy, lobular carcinoma in situ (LCIS) has been associated with an increased risk of development of a subsequent invasive breast carcinoma However, the association between LCIS and the risk of subsequent local recurrence in patients with infiltrating c arcinoma treated with conservative surgery and radiation therapy has receiv ed relatively little attention. METHODS. Between 1968 and 1986, 1625 patients with clinical Stage I-II inva sive breast carcinoma were treated at the Joint Center for Radiation Therap y at Harvard Medical School with breast-conserving surgery (CS) and radiati on therapy (RT) to a total dose to the primary site of greater than or equa l to 60 grays. Analysis was limited to 1181 patients with infiltrating duct al carcinoma, infiltrating lobular carcinoma, or infiltrating carcinoma wit h mixed ductal and lobular features who, on review of their histologic slid es, had sufficient normal tissue adjacent to the tumor to evaluate far the presence of LCIS and also had a minimum potential follow-up time of 8 years . The median follow-up time was 161 months. RESULTS. One hundred thirty-seven patients (12%) had LCIS either within the tumor or in the macroscopically normal adjacent tissue. The 8-year crude r isk of recurrence was not significantly increased for patients with LCIS as sociated with invasive ductal, invasive lobular, or mixed ductal and lobula r carcinoma. Among the 119 patients with associated LCIS adjacent to the tu mor, the 8-year rate of local recurrence was 13%, compared with 12% for the 1062 patients without associated LCIS. For the 70 patients with moderate o r marked LCIS adjacent to the tumor, the 8-year rate of local recurrence wa s 139b. The extent of LCIS did not affect the risk of recurrence. The risks of contralateral disease and of distant failure were similarly not affecte d by the presence or extent of LCIS. CONCLUSIONS. Breast-conserving therapy involving limited surgery and radiat ion therapy is an appropriate method of treating patients with invasive bre ast carcinoma with or without associated LCIS. Neither the presence nor the extent of LCIS should influence management decisions regarding patients wi th invasive breast carcinoma. [See editorial counterpoint and reply to coun terpoint on pages 978-81 and 982-3, this issue.] (C) 2000 American Cnncer S ociety.