Purpose: To look for the therapeutic benefit of radiotherapy after surgery in patients with T1–T2 breast tumour.
Methodology: From 1990 to 2000, 915 patients with T1–T2 breast tumour who underwent mastectomy or conservative breast surgery (CBS) with or without radiotherapy were analysed retrospectively for age, disease stage, radiation therapy technique, dose, the use of chemotherapy or hormonal therapy and other clinical and/or pathologic characteristics. The Kaplan–Meier method was used to estimate locoregional recurrence-free survival (LRRFS) and overall survival (OS). The Cox proportional hazard regression model was used to determine significant prognostic factors affecting LRRFS and OS.
Results: At a median follow up of 74 months, LRR rate was 5.3% and distant metastases rate was 19%. Disease-free survival (DFS) and OS at 10 year was 72% and 76%, respectively. LRR in patients with CBS followed with radiation was 3% as compared to 33% without radiation. LRR in patients with post-mastectomy radiation was 3% as compared to 19% without radiation. In patients with N0 nodes, LRR was 4% with radiation and 20% without radiation. Worst case was in patients with CBS-N0 who were not given radiation. LRR in such patients was 32% as compared to 5% in those who were given radiation post-CBS. In patients with mastectomy with N0 status, LRR was 3% with radiation as compared to 18% with out radiation. On univariate analysis factors affecting LRRFS were type of surgery, nodal involvement, radiotherapy and hormonal therapy. Factors affecting OS were nodal involvement, grade, lymphovascular invasion (LVI), ductal carcinoma in situ (DCIS), extracapsular extension (ECE), chemotherapy and radiotherapy. On multivariate analysis factors affecting LRRFS were type of surgery, nodal involvement, radiotherapy and hormonal therapy. Factors affecting OS were nodal involvement, LVI, DCIS, ECE, chemotherapy and radiotherapy.
Conclusion: Radiation use offered a therapeutic advantage for all patients with T1–T2 breast cancer.