Paravertebral Block Does Not Reduce Cancer Recurrence, but Is Related to Higher Overall Survival in Lung Cancer Surgery: A Retrospective Cohort Study

BACKGROUND: Postoperative analgesic methods are suggested to have an impact on long-term prognosis after cancer surgery through opioid-induced immune suppression. We hypothesized that regional analgesia that reduces the systemic opioid requirement would be related to lower cancer recurrence and higher overall survival compared to intravenous patient-controlled analgesia (PCA) for lung cancer surgery. METHODS: Records for all patients who underwent open thoracotomy for curative resection of primary lung cancer between 2009 and 2013 in a tertiary care hospital were retrospectively analyzed. Patients were divided by postoperative analgesic methods: PCA (n = 574), thoracic epidural analgesia (TEA, n = 619), or paravertebral block (PVB, n = 536). Overall and recurrence-free survivals were compared among 3 analgesic methods via a multivariable Cox proportional hazard model and a log-rank test after adjusting confounding factors using propensity score matching (PSM). RESULTS: Analgesic method was associated with overall survival (P=.0015; hazard ratio against TEA [95% confidence intervals]: 0.58 [0.39-0.87] for PCA, 0.60 [0.45-0.79] for PVB). After confounder adjustment using PSM, PVB showed higher overall survival than PCA (log-rank P=.0229) and TEA (log-rank P=.0063) while PCA and TEA showed no difference (log-rank P=.6). Hazard ratio for PVB was 0.66 [0.46-0.94] against PCA and 0.65 [0.48-0.89] against TEA after PSM. However, there was no significant association between the analgesic methods and recurrence-free survival (P=.5; log-rank P with PSM =.5 between PCA and TEA,.5 between PCA and PVB,.1 between TEA and PVB). CONCLUSIONS: Pain-control methods are not related to cancer recurrence. However, PVB may have a beneficial effect on overall survival of patients with lung cancer.