Regional variation in cancer survival in Norway

1

Introduction

Over the last decades, 5-year relative cancer survival generally increased steadily in all European countries, however with international disparities, as documented in EUROCARE-5, as well as in the International Cancer Benchmarking Partnership (ICBP) comparisons [12] . Additionally, regional disparities in cancer survival have been reported. In cancer patients diagnosed in Denmark, Sweden, Norway and Finland in the time period 1977–1993, a systematic regional variation was found in each country for most of the 12 cancer sites studied [3] . More recently, in Finland a significant variation in cancer survival between different municipalities and hospital districts was documented for 12 cancer sites in all 5-year periods from 1966 to 2016 [4] . In Denmark, regional variations in breast cancer, as well as melanoma survival have been reported [56] . In contrast, in Germany, for patients diagnosed with cancer in 2011, no statistically significant variation in cancer survival among the regions was found, except for one region in which lung cancer survival was below the 99.8% control limit among women [7] .

A previous analysis from Cancer Registry of Norway (CRN), including patients diagnosed with cancer in the period 2002–2011, concluded that the 5-year age-standardized relative survival differed, dependent on place of residence, for all cancer sites combined and for the six most common cancer sites in Norway. Adjustments for tumor stage explained most of the regional variation in prostate and breast cancer survival, whereas further adjustment for socioeconomic status (SES)-indicators, comorbidity and type of treatment did not materially change the regional variation in any of the sites [8] .

The unexplained regional variation in Norway has occurred despite a national, tax-funded health care system, which is intended to provide high quality and equal access to cancer care for all citizens [9] . To improve quality, over the last four decades cancer surgery has been increasingly centralized, and national cancer treatment guidelines have been implemented [10] . Since 2002, the public hospitals have been organized as local Health Trusts (HTs) within a total of five, later four, Regional Health Trusts (RHTs).

The aim of this study was to compare cancer survival between regions and within regions in Norway over time, for all cancers combined and for selected group of cancers with predominantly centralized vs. not centralized primary surgical treatment, and to relate any variation to organizational reforms.