Is Survival with Conservative Breast Therapy becoming Superior to that with Modified Radical Mastectomy alone for the Treatment of Early Breast Cancer in this Era?

Purpose: This study aims to assess survival rates in early breast cancer patients treated by Conservative breast therapy (CBT), including radiotherapy, compared to those treated by modified radical mastectomy (MRM) alone. Methods: The South Egypt Cancer Institute and the Assiut University Oncology Department patients’ records, from January 2010 to December 2017, were searched for T1-2N0-1M0 breast cancer patients treated by CBT or MRM. Patients who didn’t receive chemotherapy were excluded to reduce the treatment variation. Results: The five-year locoregional disease free survival (LRDFS) was 97.3% for the CBT patients was and 98.0% for the MRM patients (P=.675). The five-year distant disease free survival (DDFS) was 93.6% for CBS and 85.7% for MRM (P=0.033). The DFS was 91.9% for the BCT patients and 85.3% for the MRM patients (P=0.045). The five-year OS was 98.2% for the CBT patients and 94.3% for the MRM patients, (P=0.02). By Cox regression analysis, the CBT resulted in significantly better OS, (p=0.018) and the (HR=0.350, 95% CI 0.146-0.837). The adjusted OS, estimated by the propensity-score based weights, remained superior in CBT than in MRM patients (p < 0.001). Conclusion: CBT resulted in better DDFS, DFS and OS than MRM. Future randomized trials are needed to confirm these findings and determine the cause.