A Retrospective Examination of Neoadjuvant Chemotherapy for Metachronous Colorectal Peritoneal Metastases Prior to...

Neoadjuvant chemotherapy (NACT) prior to cytoreductive surgery (CRS) and heated intraperitoneal chemoperfusion (HIPEC) for patients with metachronous colorectal peritoneal metastases (CRPM) carries theoretical advantages but thus far has not demonstrated survival benefit.

We conducted a retrospective single institution study of patients with CRPM undergoing CRS/HIPEC ± NACT from 2002 to 2022.

A total of 199 patients with metachronous CRPM were identified; 128 patients (64.3%) underwent NACT while 71 patients (35.7%) underwent upfront CRS/HIPEC. The majority of patients were white (92.5%) and male (53.3%) with a median age of 57 years. There was an average of 19.5 months from initial colon cancer diagnosis to the development of CRPM, and 155 patients (77.9%) had undergone previous systemic chemotherapy in their disease course prior to development of CRPM. Patients who received NACT demonstrated no difference in PCI (median 12 vs. 10, p = .19) or rate of undergoing complete cytoreduction (81.2% vs. 93%, p = .08) versus those who underwent upfront CRS/HIPEC. Patients undergoing NACT+CRS/HIPEC experienced a significantly higher rate of major perioperative complications (25% vs. 12.7%, p = .04) and increased hospital length of stay (12 vs. 10 days, p < 0.01). There was no significant difference in median recurrence-free survival (18.7 vs. 20.3 months, p = .283) or overall survival (35.3 vs. 32.9 months, p = .513) between the groups.

Utilizing NACT prior to CRS/HIPEC for patients with metachronous CRPM did not demonstrate survival benefit. NACT was, however, associated with increased rates of perioperative complications and length of hospital stay. Further studies are needed to better evaluate the optimal role and timing of systemic chemotherapy.