Propensity score-matched evaluation of prophylactic hyperthermic intraperitoneal chemotherapy in geriatric patients with locally advanced colorectal cancer: safety and survival benefits

The role of prophylactic hyperthermic intraperitoneal chemotherapy (HIPEC) in elderly patients with locally advanced colorectal cancer (LACRC) remains controversial. This study aimed to evaluate the perioperative safety and survival benefits of HIPEC using propensity score matching (PSM). A total of 166 elderly LACRC patients who underwent curative surgery were included between January 2017 to January 2022. After 1:2 PSM, 40 patients received prophylactic HIPEC, while 80 served as controls. Postoperative complications, overall survival (OS), and disease-free survival (DFS) were compared. Multivariable Cox regression and Kaplan-Meier (KM) analyses were performed, with subgroup analysis focusing on lymph node status. The overall postoperative complication rates were comparable between the HIPEC and control groups (22.5% vs. 15.0%, P = 0.445). Multivariable Cox regression showed no significant improvement in OS or DFS with HIPEC in the overall cohort. However, in the lymph node-positive (N+) subgroup (HIPEC, n = 20; Control, n = 31; P = 0.327), HIPEC was associated with significantly better OS (P = 0.017) and DFS (P = 0.022), with a significant interaction between HIPEC and N-stage (OS: P = 0.013; DFS: P = 0.006). These associations remained significant after applying the Holm-Bonferroni correction for multiple testing within this subgroup. KM analysis confirmed prolonged survival in N+ patients receiving HIPEC (OS: P = 0.038; DFS: P = 0.038). In conclusion, prophylactic HIPEC following radical resection did not increase perioperative complications in elderly patients with LACRC. While overall survival benefits were not significant, prophylactic HIPEC significantly improved OS and DFS among patients with N+ disease. These findings suggest a selective benefit for high-risk patients, warranting further validation.