The Role of Contralateral Prophylactic Mastectomy in Invasive Lobular Carcinoma

Abstract: Invasive lobular carcinoma has been associated with an increased risk of contralateral breast disease. Controversy exists regarding the use of contralateral prophylactic mastectomy versus careful observation of the contralateral breast. Our objective was to determine the incidence of occult cancer in the contralateral breast and to assess whether contralateral prophylactic mastectomy improves patient survival. We retrospectively reviewed the charts of 133 patients treated surgically for invasive lobular carcinoma between January 1, 1978, and December 31, 1993. The median age was 54 years (range, 24–82 years). The distribution of patients by stage was as follows: stage 1, 29%; stage IIa, 36%; stage IIb, 20%; stage IIIa, 11%; stage IIIb, 3%; and unknown, 1%. The median follow‐up was 68 months (range, 13–178 months). Group comparisons were performed using log‐rank analysis and survival curves were constructed by the method of Kaplan and Meier. Eighteen patients underwent contralateral prophylactic mastectomy. Among these patients there were no cases of invasive cancer and only 3 (17%) cases of lobular carcinoma in situ in the contralateral breast. Three patients who underwent contralateral prophylactic mastectomy later developed distant metastases from the original ipsilateral breast cancer. Of the 115 patients managed conservatively, 3 (3%) developed contralateral disease at 11, 34, and 101 months. Twenty‐five patients developed distant disease. Overall survival in the contralateral prophylactic mastectomy group did not differ significantly from the group treated conservatively (p = 0.90). We conclude that careful observation with a yearly mammogram and physical examination of the contralateral breast is appropriate management for patients with invasive lobular carcinoma.