CONSERVATIVE RADIOSURGERY FOR IN-SITU DUC TAL CARCINOMA OF THE BREAST- AN ANALYSIS OF 86 CASES

Objectives: With effective screening programmes, the global incidence of in situ ductal carcinoma of the breast has risen to 15%, representi ng 20 to 30% of the mammographically detected TO tumours. Prognosis is generally good in these tumours, but treatment has in the past, parad oxically, relied on extensive surgery. We report our experience with c onservative radiosurgery performed in such cases from 1980 to 1990. Me thods: There were 86 patients with a mean age of 52 years. Initial TNM classification was T0 = 57, T1 = 17, T2 = 9 and Tx = 3. Ah underwent limited surgery (quadrantectomy: 17; lumpectomy: 69) and 49 had axilla ry dissection. All received breast irradiation with scar boost (46 - 5 0 Gy + 10 - 14 Gy with classical fractionation). Thirty one postmenopa usal women received adjuvant tamoxifen. The quality of the resection w as good in 77 cases, doubtful or incomplete in 9. In one case axillary nodal involvement was found. The histological subtype was clearly ide ntified in 63 eases. With a median follow-up of 58 months, 3 local rel apses occurred (3.4%), at 27, 48 and 52 months respectively. One was i n situ and two invasive. All were clinical lesions (2 T1 and 1 T2); tw o had incomplete or doubtful excision and all received less than 60 Gy on the tumour bed. All had mastectomy. Two are alive and well but one developed multiple metastasis. Five other women had subsequent surger y for suspicion of local relapse but all had benign disease. One devel oped contralateral disease 20 months later. Two women died subsequentl y due to a second cancer. Conclusion: These results confirm the import ance of the excision quality and suggests a possible dose-effect in th e control of in situ ductal carcinoma by radiotherapy. The recent resu lts of the B-17 NSBAP trial also conclude that the radiosurgical conse rvative treatment, for limited in situ ductal carcinoma, is a raisonna ble alternative to mastectomy.