Liver only metastatic disease in patients with metastatic colorectal cancer: Impact of surgery and chemotherapy

Background. Metastatectomy in colorectal cancer (CRC) is now a standard of care with improved survival reported. Conversion chemotherapy has increased the population who are suitable for surgery. Here we assess patterns of care and treatment outcome in liver only metastases in South Australia using the clinical registry for advanced CRC. Methods. We analysed the outcomes for patients with liver only metastatic involvement from the SA Metastatic CRC Database with the aim to investigate the role of chemotherapy on liver resection and outcome in comparison to liver resection only and chemotherapy without liver resection. Patients who had no therapy or non-surgical liver interventions were excluded for this analysis. Results. One thousand nine hundred and eight patients were available for analysis, 687 (36%) had liver only metastatic disease and 455 (24%) had active therapy as defined. In total 54.2% (247/455) had chemotherapy alone, 19.1% (87/455) had liver resection alone, and 26.6% (121/455) had combined treatment. The three-year survival for chemotherapy, resection and combined treatment subgroups is 19.5%, 73.8% and 73.7%, respectively. The addition of chemotherapy to surgery did not improve survival. Switching chemotherapy was associated with a poorer outcome; three-year overall survival for chemotherapy switch was 62.5%, compared with same regimen pre- and post-74%, and chemo post-resection 80%. Conclusion. Liver only metastatic disease is common in CRC and patients undergoing liver resection have improved long-term survival. Survival for a combined approach of chemotherapy and hepatic resection is similar to surgery alone. Patients not suitable for surgery with liver only disease have a poorer prognosis highlighting the need for improved liver-directed therapies and attempts to covert non-resectable to resectable disease if possible.