A Retrospective Study of Results of Conservative Therapy for Breast Cancer in Japan
Purpose : In Japan, the history of breast conservative breast cancer surgery with radiation therapy is shorter than in Europe and North America, and the number of patients with early breast cancer treated by these therapies has been smaller. Therefore, we consider the accumulation of the results of this conservative therapy to be important. The purpose of this study was to evaluate the results of conservative surgery with radiation therapy in Japan. Materials and Methods : The subjects of this study were 105 patients (105 breasts) with early breast cancer who received conservative surgery with radiation therapy in our institute between April 1987 and December 1993. Six patients were stage 0 (Tis), 86 patients were stage I and 13 patients were stage II. During the total course of this study, quadrantectomy (84%) was the most commonly performed procedure. A carcinoma-positive resection margin was recognized in seven patients on postoperative histological examination. In axillary lymph node dissection, level I and II lymph nodes were removed except for patients with Tis. Results: There was no failure in local control in any patients. Distant metastasis without local failure was discovered in three patients (2.9%) during follow-up of 3.0～9.7 years (median: 5.8 years). The 8-year overall survival rate was 94.0% and the 8-year disease-free survival rate was 95.8%. At present, the reason for this low incidence of local recurrence is unclear. Although the follow-up periods have not been enough, the patient selection, the type of surgery and the use of chemohormonal therapy might provide an explanation. Conclusion : Our analysis supports the continued use of conservative surgery with radiation therapy in the treatment of stage I and II breast cancer.