Breast cancer in association with lobular carcinoma in situ. Clinicopathologic review and treatment recommendation.

A 6 year follow-up study of 80 women with coexisting lobular carcinoma in situ and infiltrating breast cancer has been conducted to emphasize the natural history and management of these cancers. Treatment of the contralateral breast is of utmost importance as lobular carcinoma in situ is a multicentric neoplasm associated with a subsequent high occurrence of invasive cancer. This series has documented a high incidence of bilateral cancer. Six patients (7.5 percent) had simultaneous bilateral tumors and eight patients (10 percent) had the subsequent development of a second primary tumor, representing approximately four times the expected rate. Despite a well structured out-patient department, follow-up was suboptimal. Six of eight metachronous tumors were detected at a late stage (T2 and greater).