Determinants of long-term survival vs early failure after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for colorectal peritoneal metastases: a comparative analysis of two extreme phenotypes.

BACKGROUND

Cytoreductive surgery (CRS), hyperthermic intraperitoneal chemotherapy (HIPEC), and perioperative chemotherapy can render colorectal peritoneal metastases (CRC-PM) a curative-intent disease in selected patients. However, the factors that distinguish long-term survivors from patients who experience early failure have rarely been examined through direct comparison. We compared the 2 extreme outcome phenotypes.

METHODS

In a single-center, retrospective, comparative cohort (2007-2025), consecutive patients undergoing CRS-HIPEC for CRC-PM were identified. Long-term survivors (overall survival [OS], ≥36 months; n = 47) and early-failure patients (OS, ≤6 months; n = 61) were compared directly (n = 108); the early-failure group was defined by OS ≤6 months. Univariable comparison and multivariable binary logistic regression were used for the 2-phenotype comparison; time-to-event (Kaplan-Meier and Cox) modeling was restricted to the full cohort (n = 244) to avoid conditioning on the outcome. Analyzes were performed in SPSS version 29 (IBM Corp).

RESULTS

High peritoneal cancer index (PCI ≥14) was independently associated with early-failure group membership, and ostomy formation was also associated with early failure, most likely as a surrogate for rectal/pelvic disease (logistic regression: odds ratio, 6.21 and 5.38, respectively). In the full cohort, high PCI (hazard ratio [HR], 2.64; 95% CI, 1.25-5.55) was independently associated with shorter survival, as was ostomy formation (HR, 2.69; 95% CI, 1.28-5.66), though the latter is most likely a surrogate for rectal/pelvic disease. Compared with early-failure patients, long-term survivors had lower tumor burden, more frequent complete cytoreduction (93.6% vs 78.7%), a numerically but not significantly higher rate of neoadjuvant chemotherapy (66.0% vs 49.2%; P =.081), no grade ≥III complications, and no anastomotic leak (0% vs 11.5%).

CONCLUSION

Low peritoneal tumor burden, complete cytoreduction, and an uncomplicated postoperative course distinguish long-term survivors, whereas high peritoneal tumor burden marks early failure; ostomy formation is associated with early failure but most likely as a surrogate for rectal or pelvic disease rather than as an independent factor. These findings reinforce the central role of patient selection and complete cytoreduction, which requires meticulous surgical technique rather than purely resective effort.