Prognostic consequences of implementing cancer patient pathways in Denmark: a comparative cohort study of symptomatic cancer patients in primary care.

BACKGROUND: Cancer Patient Pathways (CPPs) were introduced in 2000-2015 in several European countries, including Denmark, to reduce the time to diagnosis and treatment initiation and ultimately improve patient survival. Yet, the prognostic consequences of implementing CPPs remain unknown for symptomatic cancer patients diagnosed through primary care. We aimed to compare survival and mortality among symptomatic patients diagnosed through a primary care route before, during and after the CPP implementation in Denmark.

METHODS: Based on data from the Danish Cancer in Primary Care (CaP) Cohort, we compared one- and three-year standardised relative survival (RS) and excess hazard ratios (EHRs) before, during and after CPP implementation for seven types of cancer and all combined (n = 7725) by using life-table estimation and Poisson regression. RS estimates were standardised according to the International Cancer Survival Standard (ICSS) weights. In addition, we compared RS and EHRs for CPP and non-CPP referred patients to consider potential issues of confounding by indication.

RESULTS: In total, 7725 cases were analysed: 1202 before, 4187 during and 2336 after CPP implementation. For all cancers combined, the RS3years rose from 45% (95% confidence interval (CI): 42;47) before to 54% (95% CI: 52;56) after CPP implementation. The excess mortality was higher before than after CPP implementation (EHR3years before vs. after CPP = 1.35 (95% CI: 1.21;1.51)). When comparing CPP against non-CPP referred patients, we found no statistically significant differences in RS, but we found lower excess mortality among the CPP referred (EHR1year CPP vs. non-CPP = 0.86 (95% CI: 0.73;1.01)).

CONCLUSION: We found higher relative survival and lower mortality among symptomatic cancer patients diagnosed through primary care after the implementation of CPPs in Denmark. The observed changes in cancer prognosis could be the intended consequences of finding and treating cancer at an early stage, but they may also reflect lead-time bias and selection bias. The finding of a lower excess mortality among CPP referred compared to non-CPP referred patients indicates that CPPs may have improved the cancer prognosis independently.