Postmastectomy radiation and survival in patients with breast cancer

Purpose: To analyze the impact of postmastectomy radiotherapy on locoregional control and overall survival in patients with carcinoma breast.
Materials and Methods: Between 1995 and 2000, 688 patients of carcinoma breast were analyzed. Out of these, 608 received postmastectomy radiotherapy and 80 patients were not given any radiation therapy. At a median follow-up of 67 months, the outcomes studied were locoregional recurrence (LRR), distant metastases, disease-free survival (DFS) and overall survival (OS) using univariate and multivariate analyses.
Results: The frequency of LRR with or without distant metastases was 8.5%, and distant metastases was seen in 18.7% of patients. On univariate analyses, factors affecting LRR were age < 40 years (0.019), tumor stage ( P = 0.001 ), grade ( P = 0.027 ), pathological nodal status ( P < 0.0001 ), deep resection plane (0.041), ER/PR status ( P = 0.032 ) and postmastectomy radiation therapy (PMRT) ( P < 0.0001 ). DFS rate was 69% at 5 years. Factors affecting distant metastases were age < 40 years (0.005), tumor stage ( P < 0.0001 ), grade ( P = 0.0007 ), pathological nodal status ( P < 0.0001 ), extra capsular extension (ECE) ( P = 0.002 ), hormonal therapy ( P < 0.0001 ) and PMRT ( P < 0.0001 ). The OS rate was 81% at 5 years. Factors affecting OS were tumor stage ( P < 0.0001 ), grade ( P = 0.0001 ), pathological nodal status ( P < 0.0001 ), ECE ( P = 0.002 ) ER/PR status ( P = 0.008 ), hormonal therapy ( P = 0.001 ) and PMRT ( P = 0.004 ). On multivariate analysis, factors affecting LRR were age ( P = 0.001 ), tumor stage ( P = 0.021 ), deep resection plane (0.003), ECE ( P = 0.022 ) and PMRT ( P = 0.047 ). Factors affecting distant metastases were menopause ( P = 0.044 ), grade ( P = 0.012 ), ECE ( P = 0.017 ) and PMRT ( P = 0.012 ). Factors affecting OS were menopausal status ( P = 0.017 ), tumor stage ( P = 0.029 ), pathological nodal status ( P = 0.011 ) and PMRT ( P = 0.002 ).
Conclusion: PMRT improves LRR as well as OS in patients with carcinoma breast. Other factors of prognostic importance were menopausal status, tumor stage and pathological nodal status.