LAUSR

BACKGROUND Although some preclinical studies have inferred that laparoscopic surgery for advanced cancer may increase the risk of peritoneal metastasis, this potential hazard has not been fully evaluated in the clinical setting. This study aimed to clarify whether laparoscopic surgery is associated with an increased risk of postoperative peritoneal recurrence after resection of T4 colon cancer. METHODS This study included 272 patients who underwent curative resection for pathological T4a colon cancer without distant metastases at the University of Tokyo Hospital between 1997 and 2017. Multivariable Fine-Gray analysis was performed to evaluate whether the use of laparoscopy was an independent risk factor for postoperative peritoneal recurrence. Thereafter, oncological outcomes (overall and relapse-free survival, and organ-specific recurrence) were compared between laparoscopic colectomy and open colectomy using propensity score matching. RESULTS Multivariable analysis found that laparoscopic surgery was a significant risk factor for postoperative peritoneal recurrence (hazard ratio: 1.89; 95% confidence interval: 1.01-3.65; P = .046). Comparison after propensity score matching revealed that the incidence of peritoneal recurrence was significantly higher after laparoscopic colectomy than after open colectomy (5-year cumulative incidence: 28.1% vs 12.1%; P = .003). CONCLUSION This study suggested that laparoscopic surgery may be related to an increased risk of peritoneal recurrence in patients with pathological T4a colon cancer. Clinicians should be fully aware of this potential risk and seek an optimal treatment plan for the prevention and early detection of peritoneal metastasis.