ASO Visual Abstract: Short-Term Outcomes Following Breast Cancer Surgery With and Without Neoadjuvant Chemotherapy: A Nationwide Administrative Database Study in Japan

Purpose: Although neoadjuvant chemotherapy (NAC) has become common for breast cancer, its impact on short-term surgical outcomes and the feasible chemotherapy–surgery interval remain unclear. Using a Japanese nationwide database, this study investigated the impact of NAC on short-term outcomes following breast cancer surgery. Methods: In this study of 11,722 patients with NAC and 120,538 patients without NAC who underwent surgery for stage 0–III breast cancer July 2010–March 2017, to cancel out site-specific effects, we generated a 1:4 matched-pair cohort matched for age, institution, and fiscal year of admission. We then conducted multivariable analyses adjusting for potential confounders to compare postoperative complications, duration of anesthesia, and total hospitalization costs. Additionally, we conducted three sensitivity analyses for patients with a short interval from NAC to surgery, patients receiving a particular NAC regimen, and patients undergoing a particular surgical procedure. Results: In total, the occurrence of postoperative complications was 6.0%, and the median interval from NAC to surgery was 31 (interquartile range, 24–39) days. The two groups did not differ significantly in terms of complications (odds ratio, 0.95; 95% confidence interval, 0.88–1.04), including local and general complications. NAC was significantly associated with shorter duration of anesthesia and lower total hospitalization costs. The sensitivity analyses showed similar results. Conclusions: Our matched-pair cohort analyses revealed no significant differences in postoperative complications between patients with and without NAC for breast cancer, regardless of the interval, regimen, and surgical procedure. Patients can safely receive surgery and NAC without a lengthened interval. © 2021, Society of Surgical Oncology.