Postmastectomy radiotherapy for early breast cancer

Abstract

OBJECTIVE: To investigate the value of postmastectomy radiotherapy for early breast cancer. METHODS: From 1983 to 1991, 605 patients with T1-2N0-1M0 breast cancer were treated by radical mastectomy in our hospital. 149 patients underwent surgery alone(S group), and the remaining 456 patients received further adjuvant treatment. Of these patients, 135 received postoperative radiotherapy(S + R group), 113 adjuvant chemotherapy or tamoxifen(S + Y group), and 208 adjuvant chemotherapy or tamoxifen plus radiotherapy(S + Y + R group). Here, chemotherapy plus tomoxifen is designated as systematically therapy. The locoregional recurrence (LRR), disease-free survival (DFS), and overall survival (OS) rates were calculated by Kaplan-Meier analysis. The differences in locoregional recurrence and survival between these groups were compared by logrank test. RESULTS: The 10-year actuarial LRR, OS and DFS rates for all patients were 13.4%, 81.6%, and 67.6%, respectively. The 10-year LRR rate was 10.3% for patients with negative axillary nodes, 9.4% for those with 1-3 positive nodes, and 25.9% for those with four or more positive nodes. The locoregional recurrence was significantly higher in patients with four or more positive nodes as compared to those with negative or 1-3 positive nodes (P < 0.05). For the S and S + R groups, the 10-year actuarial LRR rate was 18.7% in the S group and 7.5% in the S + R group (P = 0.017), the corresponding OS and DFS rates of these two groups were 82.1% and 81.1% (P = 0.618), and 65.2% and 71.6% (P = 0.457), respectively. For the S + Y and S + Y + R groups, the 10-year actuarial LRR rate was 21.1% in the S + Y group and 9.5% in the S + Y + R group (P = 0.001), There, the corresponding OS and DFS rates were 75.5% and 85.0% (P = 0.020), and 59.3% and 70.2% (P = 0.003), respectively. Only for patients with four or more positive nodes who had had systematic therapy, radiotherapy was beneficial; the 10-year actuarial LRR of patients who received systematic therapy only was 40.1% as compared with 15.1% of those who received systematic therapy plus radiotherapy; Their OS rates were 55.4% and 67.1% (P = 0.040) and their DFS rates were 30.5% and 57.3% (P = 0.001). CONCLUSION: Post-mastectomy radiotherapy is able to significantly decrease the locoregional recurrence and improve the survival of patients with four or more positive axillary nodes. We suggest that postmastectomy radiotherapy be given as routine for these patients.