Socioeconomic inequalities in treatment for colorectal liver metastases in England: A competing risk analysis using National Cancer Registration Dataset

Background There has been a wide variation, as well as socioeconomic inequalities, in liver resection rate for people diagnosed with colorectal liver metastases (CRLM) in England. Currently, service specification in England requires providers to follow locally agreed referral pathways. However, decisions about patient referral to specialist multi-disciplinary teams (MDTs) may depend on local primary site-specific MDTs. We aimed to assess socioeconomic inequalities in the probability of undergoing liver resection/ablation (liver treatment), among patients diagnosed with synchronous/metachronous liver metastases (sLM/mLM). Methods We identified patients diagnosed with colorectal cancer from 2015 to 2022 using the National Cancer Registration Dataset, and those with CRLM using the administrative dataset. We conducted a competing-risk analysis using flexible parametric regression models to estimate liver treatment-specific hazard up to one year after CRLM diagnosis by SES. We also derived cumulative probabilities of receiving treatment (CPr Ltx ), handling death as the competing event. Results The population-level CPr Ltx was 8.7% (95% confidence interval [CI] 8.5 to 9.0%) for sLM (36 660 patients) and 23.5% (95% CI 23.1 to 24.0%) for mLM (25 159 patients). The adjusted CPr Ltx gap between the least and most deprived groups reached 2.6% (1.8 to 3.5%) for sLM and 1.0% (95% CI -0.2 to 2.3%) for mLM. Conclusion Socioeconomic inequalities in liver treatment receipt persisted for sLM. Policy summary Referral of all patients with CRLM to hepato-pancreato-biliary (HPB) specialists is recommended, irrespective of SES of patients. Potential policy lever could be promoting proactive HPB specialist involvement in local colorectal multi-disciplinary meetings to reduce variation in referral. (250 words)