Comparison of cancer stage distribution in the immigrant and host populations of Norway, 1990–2014

Abstract

Cancer stage at diagnosis is the most important prognostic factor for survival. We conducted a nationwide, population-based cohort study to investigate cancer stage distribution in immigrants compared to the host population of Norway. All patients recorded in the Cancer Registry of Norway in 1990-2014 were included (17,709 immigrants and 431,936 Norwegians). Individual level sociodemographic data was obtained from Statistics Norway. Ordered logistic regression was used to estimate if immigrants were diagnosed with cancer at a more advanced stage than Norwegians. Seven cancer sites were analyzed (breast, cervix, colorectal, liver, lung and trachea, prostate and stomach). With exception of breast cancer, we did not observe a clear pattern of more advanced cancer stage distribution in immigrants compared to Norwegians. Odds ratios and corresponding 95% confidence intervals for being diagnosed with a more advanced stage of breast cancer for non-Western immigrant groups compared to Norwegians were: Eastern Europe: 1.41 (1.20-1.65), Middle East: 1.58 (1.19-2.10), sub-Saharan Africa: 1.44 (0.99-2.08), South Asia: 1.40 (1.07-1.83) and East Asia: 0.90 (0.72-1.13). Sub-analyses showed that late detection of breast cancer in young non-Western immigrants might be of particular concern. Young (<50 years) non-Western immigrants had an odds ratio of 1.40 (1.21-1.62) for more advanced stage breast cancer compared to young Norwegians.

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

“…4,29 At the individual level, behavioural explanations, like improved language skills or knowledge about the healthcare system, might be relevant. 7,8 Despite this, our analysis did not detect differences in breast cancer survival between non-Western immigrants and Norwegians, and when we condition on stage at diagnosis, breast cancer survival was potentially even better for non-Western immigrants. Social networks of immigrant populations might also develop over time and contribute to improved healthcare in the groups with long residence time.…”

“…Non-Western immigrants in Norway have lower mammography screening attendance and more advanced breast cancer stage distribution than the host population. 7,8 Despite this, our analysis did not detect differences in breast cancer survival between non-Western immigrants and Norwegians, and when we condition on stage at diagnosis, breast cancer survival was potentially even better for non-Western immigrants. Still, we highlight the poor breast cancer survival for immigrants from sub-Saharan Africa and immigrants with short residence time.…”

“…7 There are certain cancer sites and subpopulations of immigrants where survival might be a concern. Better survival from lung cancer among non-Western immigrants than Norwegians is notable and not explained by residence time, stage at diagnosis, socioeconomic factors or comorbidity.…”

“…The advanced breast cancer stage distribution previously reported for non-Western immigrants is reflected in the estimates of breast cancer survival in this study. 7 There are certain cancer sites and subpopulations of immigrants where survival might be a concern. This includes immigrants from sub-Saharan Africa and immigrants with short residence time with breast cancer, and immigrants from Eastern Europe and Balkan with melanoma and prostate cancer.…”

“…6 A previous study, investigating cancer stage distribution in immigrants compared to the Norwegian host population, showed that non-Western women had higher risk of being diagnosed with a more advanced stage of breast cancer. 7 Non-Western immigrants have also been shown to have lower attendance rate to both cervical and mammography screening. 8,9 The low screening attendance and advanced breast cancer stage distribution reported for non-Western immigrants may contribute to poor cancer survival.…”