Prophylactic hyperthermic intraperitoneal chemotherapy in T4 colorectal cancer: Can it improve the oncologic prognosis? – A propensity score matching study

Some studies show that cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC) may improve overall survival and is a possible curative treatment for selected colorectal cancer (CRC) patients with restricted peritoneal metastasis (PM). The value of HIPEC in preventing PM of CRC is still controversial.In this retrospective propensity score matching (PSM) cohort study, all patients with cT4N0-2M0 undergoing treatment at a single institution in China (2014-2018) were reviewed. The 3-year disease-free survival (DFS) was set as the primary outcome, and the 3-year PM rate was also analyzed.220 patients were included in this study for analysis. After 1:3 PSM: HIPEC (n = 45) and No HIPEC (n = 135). Through 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]. For laparoscopic surgery subgroup analyses, 3-year PM rate of patients with laparoscopic surgery was 13.8 % in No HIPEC group, and 2.6 % in HIPEC group (p = 0.070). Besides, no post-operative death occurred, the anastomotic leakage rate was 2.2 % in HIPEC group and 0.7 % in the control group (p = 0.439).Prophylactic HIPEC may improve the prognosis in patients with cT4N0-1M0 CRC, but not in cT4N2M0 CRC, and it does not significantly increase surgery-related complications. Laparoscopic surgery followed by HIPEC for T4 stage CRC may not increase risk of PM.