Purpose: To determine the 15-year outcomes for women with early stage breast cancer after breast conservation therapy.
Methods and materials: Between 1977 and 1990, 937 women with Stage I and II breast carcinoma (55% T1N0, 16% T2N0, 18% T1N1, and 11% T2N1) underwent lumpectomy, axillary lymphadenectomy, and definitive irradiation. The median patient age was 52 years. Of the 937 patients, 375 (40%) received adjuvant chemotherapy and/or hormonal therapy, including 249 (92%) of the 270 women with pathologically positive nodes. The median follow-up was 10.1 years.
Results: For the overall group, the 15-year overall survival rate was 71%, and the rate of freedom from distant metastases was 76%. The 15-year local failure rate was 19%. The 15-year contralateral breast cancer rate was 12%. The most common first events were distant failure (13%), local failure (10%), contralateral breast cancer (7%), and second malignant neoplasms (6%). The local failure rate at 10 years for favorable subsets of tumors characterized by mammographic detection, resection with negative margins, treatment with chemotherapy, and treatment with hormones was 8%, 10%, 10%, and 7%, respectively. Local failures were most commonly observed within (true recurrence), or just outside (marginal miss), the primary tumor bed (66%, 85 of 128). The rate of true recurrence or marginal miss at 5, 10, and 15 years was 5%, 10%, and 12%, respectively.
Conclusion: These high rates of survival and local control confirm that breast conservation therapy yields favorable results in women with early breast cancer into the second decade after treatment.