Prophylactic hyperthermic intraperitoneal chemotherapy in T4 colorectal cancer: Can it improve the oncologic prognosis?

Abstract

3619 Background: Previous studies have shown that T4 stage was one of the risk factors for peritoneal metastasis (PM) of colorectal cancer (CRC). However, there is paradoxical data to prove that prophylactic hyperthermic intraperitoneal chemotherapy (HIPEC) treatment is beneficial for CRC patients. Methods: In this cohort study, 220 consecutive CRC patients with T4N0-2M0 were enrolled and recorded from November 2014 to November 2018 with a 3-year follow-up following surgery. A propensity score matching (PSM) approach was applied to balance the clinicopathological characteristics. Finally, 180 patients were matched successfully to further analyze. The 3-year disease-free survival (DFS) was set as the primary outcome, and the PM rate between the two groups after PSM was analyzed. Results: Before PSM, of 220 CRC patients enrolled, the 3-year DFS was 83.9% in the HIPEC group, which was better than 67.2% in the control group. The cumulative PM incidence was 2.2% in the HIPEC group and 12.6% in the control group (p = 0.047). After PSM, 180 matched patients were formed for further analysis. The DFS and the cumulative PM rate of the patients in the HIPEC group were also better than that in the control group (p = 0.034 and 0.047, respectively). For laparoscopic surgery subgroup analyses, PM rate of the patients with laparoscopic surgery was 13.8% in the No HIPEC group, and 2.6% in the HIPEC group (p = 0.070). Through multivariable analysis, it was found that prophylactic HIPEC correlated to better DFS [hazard ratio (HR) 0.43, 95% confidence interval (CI) 0.19-0.95; p = 0.037], and N2 stage correlated to worse DFS [HR 1.97, 95% CI 1.09-3.56; p = 0.025]. Besides, no post-operative death occurred, the anastomotic leakage rate was 2.2% in the HIPEC group and 0.7% in the control group (p = 0.439). Conclusions: Prophylactic HIPEC may improve the prognosis in the patients with T4N0-1M0 CRC, but not in the T4N2M0 CRC, and it does not significantly increase the surgery-related complications. Laparoscopic surgery followed by HIPEC for T4 stage CRC is relatively safe, which does not increase the risk of PM.