Adjuvant chemotherapy as a risk factor for chronic postoperative pain after video-assisted thoracoscopic surgery: a 10-year single-centre retrospective study.

OBJECTIVES The association between adjuvant chemotherapy (AC) and chronic postoperative pain (CPP) after video-assisted thoracoscopic surgery (VATS) for lung cancer resection has not yet been reported. We, therefore, investigated the association between AC and the long-term incidence of CPP after VATS. METHODS We retrospectively reviewed 3015 consecutive patients who underwent VATS for lung cancer between 2007 and 2016. The patients were divided into 2 groups: those who received (AC group) and those who did not receive (non-AC group) AC within 3 months after VATS. Propensity score analysis was performed to adjust for baseline differences between the 2 groups. The cumulative incidence of CPP at the intervals of 3 months, over 36 months, was compared before and after matching. A Cox proportional hazards regression analysis was used to investigate the predictors of CPP after VATS. RESULTS We included and assessed 2222 patients in this study. Of these, 320 patients (14.4%) received AC within 3 months post-VATS. The cumulative incidence of CPP during 36 months post-surgery was significantly higher in the AC group than in the non-AC group, before and after matching (log-rank test; P = 0.002 and 0.027, respectively). Cox proportional hazards regression analysis also showed that AC was a significant risk factor for CPP (hazard ratio 1.62, 95% confidence interval 1.16-2.28; P = 0.005). CONCLUSIONS Our results indicate that AC is an important risk factor for CPP after VATS. Further understanding of the risk factors for CPP may facilitate its prediction and treatment.