Regional variation in cancer survival in Norway

Cancer services in Norway are intended to provide high quality services and equal access for all citizens. Still, regional variation in cancer survival has been reported. Currently, the public hospitals are organized in Health Trusts (HTs), respectively within one of four regional trusts (RHTs). We aimed to evaluate the extent and rank pattern of regional and intraregional variation in cancer survival systematically over the last three decades. We postulated that organizational reforms during this period might have modulated the variation.

Excess hazard ratios (EHR) of death from cancer were estimated for all individuals identified in The Cancer Registry of Norway as diagnosed with cancer from 1984 to 2018. The model covariates included continuous age at diagnosis, sex, cancer site, stage, 5-year time period of diagnosis and place of residence. In addition to analyses for all cancers combined, selected cohorts with predominantly centralized vs. not centralized primary surgery were evaluated.

For all cancer sites combined and for the centralized surgery cohort, the range of variation in EHR among the four regions was in the order of 0.10. The ranks among the regions were fairly consistent over time. For the not centralized surgery cohort, the range of inter-regional EHR-variation was in the order of 0.10 - 0.15, with no consistent ranks. Intra-regionally, the ranges of EHR-variation were similar, but with more complex rank patterns.

The range of inter- and intra-regional variation in cancer survival was minor, as compared to the general improvement in cancer survival in the period, with no evidence of effect from organizational reforms on regional variation.