Prognostic Impact of Curative Resection for Peritoneal Recurrence of Colorectal Cancer

Background Peritoneal recurrence (PR) of colorectal cancer is a poor prognostic factor but may be treatable by curative resection. We investigated the efficacy of this treatment and identified risk factors for postoperative recurrence. Methods The subjects were patients who underwent radical surgery for colorectal cancer between January 2006 and March 2014. Those with PR were retrospectively reviewed. Prognostic factors for overall survival (OS) and risk factors for postoperative recurrence were identified. Results Among 2256 patients, 66 had PR (2.9%). Surgical resection of PR was performed in 41 patients. Curative resection was achieved macroscopically in 38 cases without diffuse metastases in the peritoneum distant from the primary tumor and with a peritoneal cancer index < 10. In multivariate analysis, curative resection was a significant prognostic factor [hazard ratio (HR) 0.198] for better 5-year OS compared with cases without curative resection (68.7% vs. 6.3%, P < 0.001). In 28 cases with concurrent metastasis, curative resection significantly improved 5-year OS compared with no curative resection (78.7% vs. 0%, P = 0.008). In the 38 patients with curative resection, the 3-year recurrence-free survival rate was 21.4%. In multivariate analysis, concurrent metastasis was a significant risk factor [HR 3.394] for postoperative recurrence, and cases with concurrent metastasis more frequently had recurrence within 2 years after curative resection. Conclusions Curative resection improved the prognosis in patients with limited and resectable PR of colorectal cancer with or without concurrent metastasis. However, recurrence after curative resection was common and concurrent metastasis was a risk factor for this recurrence.