Breast carcinoma in situ in 167 women--incidence, mode of presentation, therapy and follow-up.

In the city of Malmö, in southern Sweden, 1693 women were diagnosed as having breast carcinoma during 1976 through 1984. Of these, 167 women had pure in situ breast carcinoma (9.9%). One hundred and thirty-two had ductal carcinoma in situ (DCIS) alone or in combination with lobular carcinoma in situ (LCIS), intracystic carcinoma and/or Paget's disease of the nipple. Thirty-three had pure LCIS and two had pure intracystic carcinomas. The incidence of breast carcinoma in situ (CIS) in women 20 years of age or older was 18.7 per 10(5) woman years with high rates of DCIS for all ages above 40, whereas a decline in incidence rate was seen for LCIS in the postmenopausal age groups. The ratio of DCIS to LCIS was 4:1. Of the 132 patients with DCIS, 46% were asymptomatic and were diagnosed by mammography, 35% presented with clinical symptoms, and 19% of the cases were incidental findings in breasts operated on for benign lesions. Mammography had been performed on all patients with DCIS and contributed to diagnosis in 75%. Sixty-one per cent of all DCIS lesions had microcalcifications suspicious for carcinoma. Eighty-nine of 132 patients with DCIS underwent fine-needle aspiration biopsy (FNAB) before surgical biopsy. FNAB was suspicious or diagnostic for carcinoma in 57/89 (64%). Of 33 cases with LCIS all but one were incidental findings. In one of 28 cases with LCIS examined by mammography there was suspicion of carcinoma. Sixteen per cent of the patients with DCIS were treated by a breast-conserving operation (BCO), the remaining patients by mastectomy (ME) (52%) or subcutaneous mastectomy (SCM) (33%) with immediate reconstruction. Thirty-three per cent of the patients with LCIS were treated by BCO, the remaining patients by ME (18%) or SCM (49%) with immediate reconstruction. Only one patient had radiotherapy postoperatively. In 60% of all CIS cases where an excisional biopsy had been performed there were further foci of CIS in the final ME/SCM specimen. After a median follow-up of 7 years for the DCIS group, three patients out of 21 treated by BCO had invasive carcinoma appearing ipsilaterally. They were alive and without symptoms of recurrent disease 2.5 to 6 years following further surgery. One patient treated by SCM died from generalized ductal breast carcinoma. In the LCIS group (median follow-up 8 years) one patient out of 11 had an invasive tubular carcinoma diagnosed 4 years after BCO. Eight years later she was alive and well after bilateral SCM.