Breast cancer recurrence and survival rates in patients who underwent breast‐conserving surgery under non‐mechanically ventilated anesthesia

BACKGROUND: Recurrence after primary treatment is an important obstacle to the curing of primary breast cancer. Less‐immunosuppressive anesthetic techniques, such as local anesthesia with lidocaine, intravenous anesthesia (IVA) with propofol, and/or sedation with midazolam under spontaneous breathing may reduce breast cancer recurrence compared with standard general anesthesia techniques such as IVA and inhalation anesthesia with opioids under mechanical ventilation. AIM: The aim of this study was to analyze the factors involved in breast cancer recurrence in patients who underwent breast‐conserving surgery (BCS) under non‐mechanically ventilated anesthesia. METHODS: The study included 491 consecutive patients with stages 0–III breast cancer who underwent BCS/axillary lymph‐node management with local anesthesia and IVA and/or sedation under non‐mechanical ventilation between May 2008 and September 2021. Survival and recurrence were assessed by retrospective cohort analysis. RESULTS: The median follow‐up period was 2565 days (range, 28–4834 days). The overall and breast cancer–specific survival rates were 92.9% and 95.6%, respectively. Twenty‐one deaths, of which 11 were breast cancer–related, occurred. Disease recurred in 29 (5.9%) patients, of whom 15 patients received neoadjuvant chemotherapy (NAC) and 14 patients received adjuvant therapy (chemotherapy in 12 cases). The surgical procedure performed, but not other clinicopathological factors [recurrence site, P stage, tumor subtype, and disease‐free interval (DFI)], differed between the NAC and adjuvant therapy groups. The DFI tended to be shorter in the NAC group than in the adjuvant therapy group. The pathological therapeutic effect grade after NAC was 1 in 12 patients and ≥2 in 3 patients. CONCLUSION: More than 50% (15/29) of patients with recurrence who underwent BCS were given NAC, but most patients did not respond to it. Similarly, adjuvant chemotherapy may not have contributed to the eradication of residual tumor cells after BCS. To reduce breast cancer recurrence in patients undergoing BCS, treatment strategies, especially for patients who do not respond to NAC or adjuvant chemotherapy, need to be developed. Non‐mechanical ventilation anesthesia may also affect the incidence of breast cancer recurrence.