Cohort study to assess geographical variation in cholangiocarcinoma treatment in England

BACKGROUND Outcomes for cholangiocarcinoma(CCA)are extremely poor owing to the complexities in diagnosing and managing a rare disease with heterogenous sub-types.Beyond curative surgery,which is only an option for a minority of patients diagnosed at an early stage,few systemic therapy options are currently recommended to relieve symptoms and prolong life.Stent insertion to manage disease complications requires highly specialised expertise.Evidence is lacking as to how CCA patients are managed in a real-world setting and whether there is any variation in treatments received by CCA patients.AIM To assess geographic variation in treatments received amongst CCA patients in England.METHODS Data used in this cohort study were drawn from the National Cancer Registration Dataset(NCRD),Hospital Episode Statistics and the Systemic Anti-Cancer Therapy Dataset.A cohort of 8853 CCA patients diagnosed between 2014-2017 in the National Health Service in England was identified from the NCRD.Potentially curative surgery for all patients and systemic therapy and stent insertion for 7751 individuals who did not receive surgery were identified as three end-points of interest.Linear probability models assessed variation in each of the three treatment modalities according to Cancer Alliance of residence at diagnosis,and for socio-demographic and clinical characteristics at diagnosis.RESULTS Of 8853 CCA patients,1102(12.4%)received potentially curative surgery.The mean[95%confidence interval(CI)]percentage-point difference from the population average ranged from-3.96(-6.34 to-1.59)%to 3.77(0.54 to 6.99)%across Cancer Alliances in England after adjustment for patient sociodemographic and clinical characteristics,showing statistically significant variation.Amongst 7751 who did not receive surgery,1542(19.9%)received systemic therapy,with mean[95%CI]percentage-point difference from the population average between-3.84(-8.04 to 0.35)%to 9.28(1.76 to 16.80)%across Cancer Alliances after adjustment,again showing the presence of statistically significant variation for some regions.Stent insertion was received by 2156(27.8%),with mean[95%CI]percentage-point difference from the population average between-10.54(-12.88 to-8.20)%to 13.64(9.22 to 18.06)%across Cancer Alliances after adjustment,showing wide and statistically significant variation from the population average.Half of 8853 patients(n=4468)received no treatment with either surgery,systemic therapy or stent insertion.CONCLUSION Substantial regional variation in treatments received by CCA patients was observed in England.Such variation could be due to differences in case-mix,clinical practice or access to specialist expertise.