Regional variation in routes to diagnosis of cholangiocarcinoma in England from 2006 to 2017

Abstract

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 via 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 via 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 via an 'other' or Unknown route. The proportion diagnosed via 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 via 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.

Keywords: Cholangiocarcinoma; Emergency presentation; Regional variation; Route to diagnosis; Two Week Wait.

Figure 1

Flow diagram of eligible patients. iCCA: Intrahepatic cholangiocarcinoma; eCCA: Extrahepatic cholangiocarcinoma; CCA: Cholangiocarcinoma; ICD: International Classification of Disease.

Figure 2

Age at diagnosis for cholangiocarcinoma cohort diagnosed in England 2006-2017.

Figure 3

Routes to diagnosis of cholangiocarcinoma patients in England, 2006-2017. GP: General practitioner.

Figure 4

Routes to diagnosis according to Cancer Alliance of residence at diagnosis. GP: General practitioner.

Figure 5

Proportion of people diagnosed via a Two Week Wait referral in each Cancer Alliance: Results from linear probability model. A: Unadjusted estimates. Inner dashed line = 2 SD difference from average. Outer dashed line = 3 SD difference from average; B: Adjusted estimates. Inner dashed line = 2 SD difference from average. Outer dashed line = 3 SD difference from average. Adjustment for: age, gender, income deprivation quintile, Charlson comorbidity index, underlying liver disease, diagnosis year, tumour morphology and sub-type.

Figure 6

Proportion of people diagnosed via an emergency presentation in each Cancer Alliance: Results from linear probability models. A: Unadjusted estimates. Inner dashed line = 2 SD difference from average. Outer dashed line = 3 SD difference from average; B: Adjusted estimates. Inner dashed line = 2 SD difference from average. Outer dashed line = 3 SD difference from average. Adjustment for: Age, gender, income deprivation quintile, Charlson comorbidity index, underlying liver disease, diagnosis year, tumour morphology and sub-type.