Two thirds of the breast cancer cases in Heidelberg were treated with breast-preserving therapy (BCT). A reduction in tumor size with preoperative chemotherapy meant that the number of cases could be increased. Segment resection must, however, take place well into healthy tissue, and high-dose irradiation with the boost technique is standard procedure. A prospective randomized comparison showed that the five- to ten-year survival rate was 10% better following BCT than after mastectomy. Local recurrence after five years occurred in 4 to 6% of the cases, in 9% of the cases after mastectomy without postoperative irradiation. Even after ten years, local recurrence did not lower the survival rate. The rate of distant metastases was significantly higher in patients who did not receive postoperative irradiation after tumorectomy. For this reason irradiation must only be omitted in exceptional cases. There was no evidence of local recurrence in 90% of those women who died of distant metastases. Two years after treatment 98% of the women indicated that they would still give BCT preference over mastectomy.