Outcomes Following Treatment with FOLFOX for Patients with Resectable or Potentially Resectable Metastatic Colorectal Cancer: A Population-based Cohort Study

Aims: To evaluate the safety and effectiveness of oxaliplatin-based combination chemotherapy for patients with metastatic colorectal cancer (mCRC) to extrahepatic sites.

Materials and methods: We conducted a population-based retrospective study examining the safety and effectiveness of perioperative oxaliplatin for resectable or potentially resectable colorectal metastases in Ontario, Canada. Outcomes were also compared with patients with liver-only metastases. Patients received oxaliplatin for mCRC between 1 January 2013 and 30 June 2020.

Results: In total, 192 patients had extrahepatic metastases. Seventy per cent had R0 metastasectomy. The 3-year disease-free survival and overall survival were 62% and 79%, respectively; <4% of patients died within 60 days of metastasectomy and 74-90% of patients received treatment according to recommendations from a multidisciplinary setting. Compared with liver-only controls (n = 1306), patients had mCRC to the lung only (n = 115), lung and liver (n = 55) and liver with non-pulmonary site (n = 22). Extrahepatic metastases were more likely to be found for patients whose primary colorectal resection had positive margins (14% versus 7%, P = 0.005) and primary tumours located in the rectum [odds ratio 4.01 (2.31-6.97)]. After adjustment, there was no difference in overall survival between liver-only controls and patients with lung-only [hazard ratio 0.82 (0.59-1.15)] or liver and lung metastases [hazard ratio 1.26 (0.85-1.87)] (P = 0.24). In total, 79/115 (69%) of patients with lung-only metastases had a metastasectomy compared with 645/1306 (49%) and 15/55 (27%) of patients with liver-only and liver and lung metastases, respectively. Hospital visits were similar between patients with liver-only and extrahepatic metastases.

Conclusion: Oxaliplatin-based chemotherapy for patients with resectable or potentially resectable mCRC with extrahepatic metastases was safe and resulted in similar outcomes in appropriately selected patients when compared with patients with liver-only metastases.