Regional Variation in Routes to Diagnosis of Cholangiocarcinoma in England from 2006 to 2017

Background: Incidence of cholangiocarcinoma (CCA) is rising, with overall prognosis re-maining very poor. Reasons for the high mortality of CCA include its late presentation in most patients, when curative options are no longer feasible, and poor response to systemic therapies for advanced disease. Late presentation presents a large barrier to improving outcomes and is often associated with diagnosis mergency presentation (EP). Earlier diagnoses may be made by Two Week Wait (TWW) referrals through General practitioner (GP). We hypothesise that TWW referrals and EP routes to diagnosis differ across regions in England.

Aim: To investigate routes to diagnosis of CCA over time, regional variation and influencing factors.

Methods: We linked patient records from the National Cancer Registration Dataset to Hospital Episode Statistics, Cancer Waiting Times and Cancer Screening Programme datasets to define routes to diagnosis and certain patient characteristics for patients diagnosed 2006-2017 in England. We used linear probability models to investigate geographic variation by assessing the proportions of patients diagnosed TWW referral or EP across Cancer Alliances in England, adjusting for potential confounders. Correlation between the proportion of people diagnosed by TWW referral and EP was investigated with Spearman's correlation coefficient.

Results: Of 23632 patients diagnosed between 2006-2017 in England, the most common route to diagnosis was EP (49.6%). Non-TWW GP referrals accounted for 20.5% of diagnosis routes, 13.8% were diagnosed by TWW referral, and the remainder 16.2% were diagnosed an 'other' or Unknown route. The proportion diagnosed a TWW referral doubled between 2006-2017 rising from 9.9% to 19.8%, conversely EP diagnosis route declined, falling from 51.3% to 46.0%. Statistically significant variation in both the TWW referral and EP proportions was found across Cancer Alliances. Age, presence of comorbidity and underlying liver disease were independently associated with both a lower proportion of patients diagnosed TWW referral, and a higher proportion diagnosed by EP after adjusting for other potential confounders.

Conclusion: There is significant geographic and socio-demographic variation in routes to diagnosis of CCA in England. Knowledge sharing of best practice may improve diagnostic pathways and reduce unwarranted variation.