Simultaneous bilateral cancer of the brease--evaluation of the use of a contralateral biopsy.

During a five-year period 299 female patients with breast cancer were treated by mastectomy. In 170 of the patients a biopsy of the contralateral upper lateral quadrant was performed during the operation. In 164 of the patients with primary carcinoma of ductal origin only 7 cases of malignancy in the contralateral biopsy were observed. In six females (3.5%) the primary cancer was of lobular origin and in three of these patients (50%) the contralateral biopsies showed lobular carcinoma in situ (LCIS). It is concluded that random contralateral biopsies of the breast should be restricted to patients with a primary cancer of lobular origin.