Prophylactic hyperthermic intraperitoneal chemotherapy is associated with improved disease-free survival in...

Pathologic T4 colorectal cancer (CRC) carries a high risk of peritoneal recurrence despite curative resection. Early postoperative hyperthermic intraperitoneal chemotherapy (HIPEC) may enhance intraperitoneal cytotoxic exposure and improve recurrence control. We evaluated whether prophylactic HIPEC administered within one week of surgery improves outcomes in pathologic T4 (pT4) CRC.

We conducted a single-center, retrospective cohort study of consecutive patients with pathologically confirmed pT4 colorectal adenocarcinoma (2018-2022). Prophylactic HIPEC consisted of intraperitoneal 5-fluorouracil (650 mg/m²) perfused for 60 min at 43.0 ± 0.1 °C within one postoperative week. A 1:2 propensity score match yielded a balanced cohort (99 HIPEC; 198 non-HIPEC). The primary endpoint was disease-free survival (DFS); secondary endpoints included overall survival (OS) and site-specific recurrence. Robustness of findings was examined with sensitivity analyses.

Among 690 screened patients, 471 were eligible (155 HIPEC; 316 non-HIPEC). In the matched cohort, Kaplan-Meier comparisons were not statistically significant for DFS (log-rank p = 0.074) or OS (p = 0.460). In multivariable Cox models, HIPEC was associated with improved DFS (hazard ratio [HR] = 0.58, 95% confidence interval [CI] 0.38-0.88; p = 0.012) but not OS (HR = 0.72, 95% CI 0.41-1.24; p = 0.237). Peritoneal, hepatic, and pulmonary recurrence rates were comparable between groups, while other-site recurrence was lower with HIPEC (5.1% in HIPEC and 13.1% in non-HIPEC; p = 0.032). Results were directionally consistent across sensitivity analyses.

Prophylactic HIPEC delivered within one postoperative week was associated with improved DFS, without an observed OS advantage over the study interval, in patients with pT4 CRC. These data support selective use of early postoperative HIPEC as an adjunct to curative resection, with patient counseling focused on anticipated gains in recurrence control and the current uncertainty regarding long-term survival.