Outcomes after curatively intended treatment of limited peritoneal metastases and thermal ablation for liver metastases from colorectal cancer.

Objectives: Peritoneal metastases (PM) and liver metastases (LM) are present simultaneously in up to 2 % of patients at the time of their colorectal cancer (CRC) diagnosis. Curatively intended treatment includes cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) combined with LM resection. A less invasive treatment for LM is ablation. We aimed to estimate overall survival (OS), disease-free survival (DFS) and postoperative data in patients managed simultaneously with CRS, HIPEC and radiofrequency ablation (RFA) as first choice.

Methods: This was a retrospective national cohort study. All patients were treated at Aarhus University Hospital; the only CRS+HIPEC centre in Denmark. We included CRC patients managed with curative intent for simultaneously diagnosed PM and LM in the period January 2016 - December 2021. LM was treated with RFA as first choice, if possible. Survival was calculated by the Kaplan-Meier method.

Results: A total of 25 patients were included, the median age was 60 years (range 43-75 years) and 15 (60 %) were females. The median peritoneal cancer index was 7 (range 0-12), the median number of LM was 1 (range 1-3). Ablation was performed as the only treatment for LM in 18 (72 %) patients. After a median follow-up time of 17.1 months (range 4-36 months), the median OS was 28.6 months (95 % confidence interval (Cl) 15.8;36.1), 1-year OS was 84.0 % (95 % Cl 62.8;93.7). Median DFS was 6.1 months (95 % Cl 4.0;10.3). Median LOS was ten days (range 5-26 days). Both 30-day and 90-day mortality were 0 %.

Conclusions: The selected treatment modality (RFA) for CRC patients with both LM and PM was safe. However, DFS was low. Further research is warranted to investigate if RFA is as effective as LM resection.