Aichi Cancer Center 10-year experience with conservative breast treatment of early breast cancer: retrospective analysis regarding failure patterns and factors influencing local control.

PURPOSE: We analyzed the clinical results of conservative breast therapy in our institute to determine the risk factors influencing local and distant disease recurrence. METHODS AND MATERIALS: From 1989 to 1997, 301 breasts of 295 women with early breast cancer were treated with conservative surgery and adjuvant radiotherapy. There were 212 incidences of Stage I breast cancer, and 89 of Stage II. Patients were routinely treated with local resection, axillar dissection, and 46--50 Gy irradiation given in 23--25 fractions. Some also received a radiation boost to the tumor bed. RESULTS: The 5-/8-year overall survival, disease-free survival, and local control rates were 93.2/91.5%, 86.0/80.6%, and 95.1/92.5%, respectively. Using both univariate and multivariate analyses, tumor volume, estrogen receptor status, and age < 40 years were significant prognostic factors for disease-free survival. Both age < 40 years and surgical method had a strong effect on local control by uni- and multivariate analysis. Surgical margin status was a significant prognostic factor for local control at the univariate level (p < 0.0001), though it had only borderline significance at the multivariate level (p = 0.08). No patient experienced severe morbidity due to radiotherapy. CONCLUSION: The results obtained are comparable to previously reported data. Although the follow-up period was too short to draw definite conclusions about long-term outcomes, the outcome from conservative breast treatment was acceptable.