Preoperative radiotherapy is not associated with increased post-mastectomy short-term morbidity: Analysis of 77, 902 patients

Background: Neoadjuvant radiotherapy (NRT) enhances breast-conserving surgery outcomes, reducing local recurrence of breast cancer and increasing median survival. However, its effect on postoperative morbidity remains under-studied. We sought to assess the impact of NRT on 30-day postoperative morbidity after mastectomy. Methods: We analyzed data from women undergoing mastectomy (with or without immediate reconstruction) using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) 2005-2011 datasets. ACS-NSQIP is a prospective, risk-adjusted, outcomes-based registry. Data included demographic and perioperative factors. Outcomes studied included surgical site (wound and prosthesis/flap complications), systemic (cardiac, respiratory, neurological, urinary, and venous thromboembolism events), and overall morbidity. Logistic regression was used to estimate the unadjusted odds ratio (uOR) and adjusted odds ratio (aOR) between NRT and postoperative 30-day morbidity. Results: The study population included 77, 902 women, of which 61, 039(78.4%) underwent mastectomy only and 16, 863 (21.6%) underwent mastectomy with immediate breast reconstruction. NRT was administered to 266 (0.4%) mastectomy-only and 75 (0.4%) immediate breast reconstruction patients. In the mastectomy-only group, there were no significant differences in the rates of postoperative surgical site morbidity (aOR = 1.41; 95% confidence interval (CI):0.76-2.63; P = 0.276), systemic morbidity (aOR = 0.72; 95% CI: 0.40-1.26; P = 0.252), and overall morbidity (aOR = 0.85; 95% CI: 0.54-1.33; P = 0.477) between NRT and control groups. Similarly, no significant differences were found for these three outcomes in the immediate breast reconstruction population. Statistical power for every comparison was >80%. Conclusions: This study suggests that NRT is not associated with significantly higher 30-day postoperative complications among breast cancer patients undergoing mastectomy with or without immediate breast reconstruction.