Are cure rates for breast cancer improved by local and regional anesthesia?

Background and Objectives Recent preclinical basic science studies suggest that patient tumor immunity is altered by general anesthesia (GA), potentially worsening cancer outcomes. A single retrospective review concluded that breast cancer patients receiving paravertebral block and GA had better cancer outcomes compared with patients receiving GA alone. This study has not been validated. We hypothesized that local or regional anesthesia (LRA) would be associated with better cancer outcomes compared with GA. Methods We retrospectively reviewed a prospectively collected database to identify all stage 0-III breast cancer patients undergoing surgery in a single center during a 9-year period ending January 1, 2010. Patients were divided into 2 groups: those who received only LRA and those who received GA. Overall survival (OS), disease-free survival (DFS), and local regional recurrence (LRR) were calculated using the Kaplan-Meier method with log-rank comparison before and after propensity score matching. Results Median age of the 1107 patients who met study criteria was 64 years (range, 24-97 years). Median and longest follow-up were 5.5 and 12.5 years, respectively. General anesthesia was used for 461 patients (42%), and 646 (58%) received LRA. The point estimates of cumulative OS, DFS, and LRR "free" rates at 5 years for the GA and LRA groups were 85.5% and 87.1%, 94.2% and 96.1%, and 96.3% and 95.8%, respectively. Cox regression showed no significant differences between the 2 groups (GA and LRA) for the 3 outcomes: OS (hazard ratio [HR], 0.81; 95% confidence interval [CI], 0.59-1.10; P = 0.17), DFS (HR, 0.91; 95% CI, 0.55-1.76; P = 0.87), and LRR (HR, 1.73; 95% CI, 0.83-3.63; P = 0.15). Conclusions Breast cancer OS, DFS, and LRR were not affected by type of anesthesia in our institution. This result differs from that of the only prior published clinical report on this topic and does not provide clinical corroboration of the basic science studies that suggest oncologic benefits to LRA.