Long-Term Cytoreduction Outcomes With or Without Heated Intraperitoneal Chemotherapy For Colorectal Peritoneal Metastases.

BACKGROUND

Patients with peritoneal metastases from colorectal adenocarcinoma (CRC) benefit from cytoreductive surgery (CRS). However, the role of heated intraperitoneal chemotherapy (HIPEC) remains unclear. We studied associations between HIPEC, peritoneal disease-free survival (PDFS), and overall survival (OS) in patients with CRC undergoing CRS.

STUDY

DESIGN

All patients with CRC undergoing CRS between 2008 and 2023 were retrospectively identified at our center. Patient clinicodemographic factors were determined by chart review. OS and PDFS were evaluated using the Kaplan-Meier method. Associations between clinical factors and survival were determined using Cox proportional hazard models.

RESULTS

A total of 147 patients were identified with 24.5-month median follow-up. Most patients (111; 75.5%) had a low peritoneal cancer index (PCI; less than 11), whereas 36 patients (24.5%) had high PCI (11 or more). Eighty-three patients (55.8%) had CRS alone. Sixty-four patients underwent CRS with HIPEC (42 [66%] mitomycin C [MMC], 19 [30%] oxaliplatin [OX], 3 [4.7%] cisplatin). The median OS was 59.8 (95% CI 41.7 to 83.0) months. The median PDFS was 13.3 (95% CI 10.4 to 18.5) months. OS was equivalent comparing HIPEC with MMC, HIPEC with OX (hazard ratio [HR] 0.49, 95% CI 0.22 to 1.09, p = 0.08), and CRS alone (HR 0.74, 95% CI 0.41 to 1.32, p = 0.31). Multivariable analysis showed only PCI was associated with OS (HR 1.08, 95% CI 1.03 to 1.14, p = 0.003). Low PCI patients had similar PDFS after CRS-HIPEC (HR 1.07, 95% CI 0.61 to 1.87, p = 0.814) compared with CRS alone. High PCI patients had improved OS comparing CRS-HIPEC with CRS (MMC: HR 0.17, 95% CI 0.04 to 0.76, p = 0.02; OX: HR 0.048, 95% CI 0.006 to 0.37, p = 0.004).

CONCLUSIONS

HIPEC was not associated with OS or PDFS in patients with PCI 10 or less but was associated with improved OS and PDFS in patients with PCI 11 or more. The use of HIPEC for high PCI may be warranted, although randomized prospective data are needed to confirm this.