A contribution to the natural history of breast cancer. IV. Lobular carcinoma in situ and its relation to breast cancer.

We studied 52 patients with lobular carcinoma in situ (LCIS) of the breast, tissue being available from both breasts in 46 patients. Detailed histological examination of the tissue was combined with specimen radiography. By this technique, six invasive cancers were detected within 2 years of the primary diagnosis. five of these six carcinomas were clinically occult and were not suspected at specimen radiography. Three other invasive cancers were discovered 4 years, 7 years, and 10 years after diagnosing LCIS. The extent of the LCIS in the primary biopsy was the only feature which gave a guide to the possible presence and location of an occult invasive lesion.