Differences in management and outcome for colon and rectal carcinoma with synchronous liver metastases: a population‐based cohort study

AIM: Surgical treatment of colorectal cancer with synchronous colorectal liver metastases (SCRLM) can follow three different strategies with regard to the timing of liver resection. The aim of this study was to describe the selection of surgical strategy, focusing on differences between colon and rectal cancer with SCRLM, postoperative morbidity/mortality and survival. METHOD: This was a retrospective population‐based study of patients with SCRLM registered in the Swedish Colorectal Cancer Registry in the Stockholm/Gotland region during 2010–2017 and treated with surgical resection of the primary tumour and liver metastases (LM). Patients were followed for 5 years or censored at 22 November 2018. RESULTS: A total of 238 patients met the inclusion criteria during the study period. Patients with rectal cancer were treated with the ‘liver first’ strategy in 70% of cases, whereas the main treatment strategies for colonic tumours were ‘simultaneous resection’ (44%) and ‘primary first’ (37%). Rectal cancer had a superior 5‐year survival rate compared with colon tumours with SCRLM (62 vs. 47%; p = 0.033). There was no difference in survival between treatment strategies irrespective of primary tumour location. Postoperative complications occurred most commonly among rectal tumours treated with simultaneous resection (p = 0.024). CONCLUSION: Patients with rectal cancer and SCRLM were more often treated with the ‘liver first’ strategy than patients with colon cancer. Patients with rectal cancer and SCRLM where both primary tumour and LM were operated on had significantly better survival than corresponding patients with colon cancer.