• We reviewed the courses of 250 consecutive women with lobular carcinoma in situ of the breast entered into the Surveillance, Epidemiology, and End Results program of the Michigan Cancer Foundation, Detroit, Mich, between 1973 and 1986. No patient had known invasive cancer at the time of initial entry. The average follow-up was 93.1 months; 212 patients had mastectomy for the initial lesion and 65 patients had less than mastectomy, of whom one developed a new lesion in the ipsilateral breast. Thirty-seven patients (14.8%) were later found to have lesions in the contralateral breast, 25 within the first year. Thirteen of the 38 lesions (5.2% of the total series) were invasive, and 11 were primarily ductal. Seventeen patients died, two of breast cancer, two of unknown causes, and 13 of non—breast-related causes. The maximum mortality from breast cancer is 1.6% to this point. The frequency of mastectomy fell from 78.1% in the years 1973 through 1983 to 52% in 1984 through 1986, reflecting a change in surgical philosophy. Although no guarantees can be given to any individual patient, the great majority of patients with LCIS unassociated with a proved invasive cancer can be safely treated with less than mastectomy.
(Arch Surg. 1992;127:904-909)