Preoperative chemotherapy in colorectal peritoneal metastatic disease - a real-world observational cohort study

The effects of preoperative chemotherapy have been poorly studied in colorectal cancer with peritoneal metastases (CRC-PM). This study evaluated preoperative chemotherapy from the first multi-disciplinary team meeting (MDT) decision, focusing on the response rates, surgical outcomes, and survival.

This retrospective cohort study analyzed consecutive patients with resectable or potentially resectable CRC-PM evaluated at Uppsala University Hospital's peritoneal-MDT between March 2019 and December 2023. Kaplan-Meier curves and Cox-regression analyses were used for survival analysis.

Of 179 patients, 81 underwent upfront surgery; 52 received doublet chemotherapy and 46 received doublet with targeted therapy. Targeted group showed a 52 % overall response rate vs. 36 % for doublet group (p=0.14), with patients selected for CRS and HIPEC at a 52 % vs. 31 % rate, respectively, p=0.086. The median overall survival was superior in the targeted group than in the doublet group (intention-to-treat with all patients included): 21 (95 %CI: 18-35) vs. 17 (95 %CI: 14-22) months (p=0.027). The VEGF-targeted therapy outperformed EGFR-targeted therapy: 32 (95 %CI: 21-Not reached) vs. 15 (95 %CI: 11-40) months (p=0.042).

Preoperative chemotherapy with targeted antibodies improves overall survival in CRC-PM in patients that are not candidates for upfront CRS and HIPEC. Bevacizumab is associated with improvement over EGFR targeted treatment in a subgroup analysis.