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 5 258,675). 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.

Socioeconomic environment and disparities in cancer survival for 19 solid tumor sites: An analysis of the French Network of Cancer Registries (FRANCIM) data

“…population‐based registries data, ecological deprivation index, net survival) also showed lower survival among patients living in the most deprived environments compared to those living in the least deprived ones, for most cancer sites . More broadly, all studies investigating social inequalities in cancer survival worldwide have reported lower survival among the most deprived for a large majority of cancer sites, with no significant inverse association . Our findings are therefore supported by those from the literature, and bring new information about the situation in France and the impact of social deprivation on cancer survival for cancer sites with mitigated results in the literature (such as stomach, ovary, melanoma, thyroid, CNS or pancreas).…”

“…The lower survival found among patients living in the most deprived areas compared to those living in the least deprived ones regarding colon‐rectum cancer, breast cancer and cervical cancer might result from inequalities in cancer screening uptake, which have been identified in several French studies . Additionally, disparities in stage at diagnosis and therapeutic management according to deprivation have been related to cancer survival inequalities in previous research . However, neither stage at diagnosis nor patients’ treatment history were available in the cancer registries data used for our study.…”

“…Underlying hypotheses have been proposed by previous research and comprise a more advanced stage at diagnosis, worse access to healthcare services, less optimized choices of treatment, as well as higher prevalence of comorbid illnesses and more frequent unhealthy lifestyle among the more socially disadvantaged . Individual socioeconomic characteristics are known to be strong predictors of cancer survival as revealed in many studies worldwide . However, some of the potential explanations mentioned above as well as previous research suggest that not only individual but also contextual and environmental factors might contribute to social inequalities in cancer survival.…”

Rural–urban residence and cancer survival in high‐income countries: A systematic review

“…1,2 The majority of studies that have investigated the association between area of residence and cancer survival were conducted in high-income countries, but the findings have been inconsistent. [3][4][5][6][7][8] Furthermore, the potential roles of stage at cancer diagnosis, comorbidity, treatment, and health-related lifestyle factors in rural/urban differences in cancer outcomes have not been fully explored. A review conducted in 1992 of patterns of cancer mortality and survival in rural and urban regions suggested that residents of rural areas were more likely to be diagnosed at advanced stage compared with those living in urban communities.…”

Differences in cancer survival between immigrants in Norway and the host population

“…In Norway, both socioeconomic and geographic differences in cancer survival have been demonstrated. 2,3 At the same time, the close relationship between the social determinants of health and migration raises concerns about the health of the immigrant population. 4 In 2017, immigrants constituted 14% of the Norwegian population.…”