title: Regional variations in cancer survival: Impact of tumour stage, socioeconomic status, comorbidity and type of treatment in Norway.
abstract: Cancer survival varies by place of residence, but it remains uncertain whether this reflects differences in tumour, patient and treatment characteristics (including tumour stage, indicators of socioeconomic status (SES), comorbidity and information on received surgery and radiotherapy) or possibly regional differences in the quality of delivered health care. National population-based data from the Cancer Registry of Norway were used to identify cancer patients diagnosed in 2002-2011 (n = 258,675). We investigated survival from any type of cancer (all cancer sites combined), as well as for the six most common cancers. The effect of adjusting for prognostic factors on regional variations in cancer survival was examined by calculating the mean deviation, defined by the mean absolute deviation of the relative excess risks across health services regions. For prostate cancer, the mean deviation across regions was 1.78 when adjusting for age and sex only, but decreased to 1.27 after further adjustment for tumour stage. For breast cancer, the corresponding mean deviations were 1.34 and 1.27. Additional adjustment for other prognostic factors did not materially change the regional variation in any of the other sites. Adjustment for tumour stage explained most of the regional variations in prostate cancer survival, but had little impact for other sites. Unexplained regional variations after adjusting for tumour stage, SES indicators, comorbidity and type of treatment in Norway may be related to regional inequalities in the quality of cancer care.
authors.affiliation: Department of Registration, Cancer Registry of Norway, Institute of Population-Based Cancer Research, Majorstuen, Oslo, Norway.
authors.forename: Katrine Damgaard
authors.initials: KD
authors.lastname: Skyrud
authors.affiliation: Section of Cancer Surveillance, International Agency for Research on Cancer, Lyon Cedex 08, France.
authors.forename: Freddie
authors.initials: F
authors.lastname: Bray
authors.affiliation: Department of Digestive and Paediatric Surgery, Oslo University Hospital, Oslo, Norway.
authors.forename: Morten Tandberg
authors.initials: MT
authors.lastname: Eriksen
authors.affiliation: Department of Registration, Cancer Registry of Norway, Institute of Population-Based Cancer Research, Majorstuen, Oslo, Norway.
authors.forename: Yngvar
authors.initials: Y
authors.lastname: Nilssen
authors.affiliation: Department of Registration, Cancer Registry of Norway, Institute of Population-Based Cancer Research, Majorstuen, Oslo, Norway.
authors.forename: Bjørn
authors.initials: B
authors.lastname: Møller
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D009664:Norway / Q000453:epidemiology; D011379:Prognosis; D012042:Registries; D012923:Social Class; D012959:Socioeconomic Factors
keywords: cancer; flexible parametric models; regional variation; relative excess risk; relative survival; socioeconomic status