The clinical management of a normal contralateral breast in patients with lobular breast cancer.

Ninety-nine patients with the diagnosis of lobular carcinoma (LC) treated between 1970 and 1981 were reviewed. Thirteen patients had a contralateral mastectomy for duct cancer (DC) before the diagnosis of LC. Ten of the remaining 86 patients (11%) had simultaneous bilateral cancers detected by either physical examination or mammography, none by blind biopsy. Three of the surviving 38 patients (7.8%) developed a contralateral cancer an average of 143 months after operation. In comparison 167 patients with DC treated during the same period of time had a 1.8% incidence of synchronous cancer but the same incidence of subsequent cancer (7%). Lobular carcinoma in situ was not a reliable marker for predicting the presence of cancers in the contralateral breast. The diagnosis of LC is not an indication for either biopsy or removal of a normal contralateral breast.