Lobular carcinoma in situ of the breast. An approach to rational treatment.

A review of 3299 benign breast lesions was carried out. Lobular carcinoma in situ (LCIs) was discovered in 52 cases; and of these, 44 had been treated by biopsy alone. During the follow-up period averaging 15.9 years, 11 patients developed invasive breast cancer (IBC): 9 ipsilateral lesions, and 4 contralateral. This was about 12 times the frequency expected. The development of IBC had no relation to the patient's age, nor could any correlation be drawn between the time periods which elapsed from the time of the diagnosis of the in situ cancer to the development of IBC. The ipsilateral occurrence of IBC was not isgnificantly different from the contralateral. Careful lifelong follow-up seems to be the rational treatment for women whose breast biopsy shows LCIs.