In the hope that women with breast cancer unsuitable for primary tumorectomy would benefit from a conservative treatment, we tried to reduce the lesional volume by an initial irradiation of 45 Gy administered in 25 fractions over 35 days. This treatment was applied to 111 patients (69 T2; 42 T3). In 44 cases (40 per cent), tumoral regression enabled a secondary tumorectomy to be performed. In 16 cases (14 per cent), the tumour totally disappeared, and an additional irradiation by endocurietherapy in intermediate dosage could be given. In 51 patients (46 per cent), the tumoral response was poor and the patients underwent, depending on their wishes, either mammectomy (9 cases; 8 per cent) or high-dose endocurietherapy (42 cases; 38 per cent). Analysis of tumoral regression according to size, histological type and mammographic image provided for a better identification of good responders. The cosmetic and oncological results of this preliminary study are satisfactory, with a 95 per cent local control at 5 years after secondary tumorectomy.