Lung cancer incidence differences in migrant men in Belgium, 2004-2013: histology-specific analyses.

BACKGROUND: Immigrants make up an important share of European populations which has led to a growing interest in research on migrants' health. Many studies have assessed migrants' cancer mortality patterns, yet few have studied incidence differences. This paper will probe into histology-specific lung cancer incidence by migrant origin aiming to enhance the knowledge on lung cancer aetiology and different risk patterns among population groups. METHODS: We used data on all lung cancer diagnoses during 2004-2013 delivered by the Belgian Cancer Registry individually linked with the 2001 Belgian Census and the Crossroads Bank for Social Security. Absolute and relative inequalities in overall and histology-specific lung cancer incidence have been calculated for first-generation Italian, Turkish and Moroccan migrant men aged 50-74 years compared to native Belgian men. RESULTS: Moroccan men seemed to be the most advantaged group. Both in absolute and relative terms they consistently had lower overall and histology-specific lung cancer incidence rates compared with native Belgian men, albeit less clear for adenocarcinoma. Turkish men only showed lower overall lung cancer incidence when adjusting for education. On the contrary, Italian men had higher incidence for overall lung cancer and squamous cell carcinoma, which was explained by adjusting for education. CONCLUSIONS: Smoking habits are likely to explain the results for Moroccan men who had lower incidence for smoking-related histologies. The full aetiology for adenocarcinoma is still unknown, yet the higher incidence among Italian men could point to differences in occupational exposures, e.g. to carcinogenic radon while working in the mines.

Breast cancer by migrant background in Belgium: Lower risk, but worse survival in women of non-European origin.

Foreign and native populations differ in terms of breast cancer outcomes. Studies rarely distinguish between premenopausal and postmenopausal breast cancer, although the risk profile is different; nor between migrants of the first and second generation (FG and SG), which is crucial to examine genetic and environmental influences on breast cancer. This research fills these gaps by investigating patterns in breast cancer incidence and survival in different migrant groups by menopausal and migrant generational status, taking various risk factors into account. To this end, individually linked data from the 2001 census, the Belgian Cancer Registry and the Crossroads Bank for Social Security are used. Age-standardised incidence rates and incidence rate ratios are calculated by migrant background group, stratified according to ages 30-50 (premenopausal) and 50-70 (postmenopausal). Incidence rate ratios are examined with and without taking reproductive factors and socioeconomic position (SEP) into account. Relative survival percentages and relative excess risks of dying among premenopausal and postmenopausal patients are computed with and without controlling for the stage at diagnosis and SEP. Premenopausal breast cancer is further examined by migrant generational status. Breast cancer incidence is lower among non-European migrants compared to Belgians. Keeping SEP and known risk factors constant reduces much, but not all of the observed discrepancies. A risk convergence between SG migrants and Belgians for the development of premenopausal breast cancer is observed. Premenopausal breast cancer survival is worse among Moroccan patients due to a higher stage at diagnosis. This disadvantage is concentrated in the FG.

The effect of the Flemish breast cancer screening program on breast cancer-specific mortality: A case-referent study.

BACKGROUND: Breast cancer screening programs were introduced in many countries worldwide following randomized controlled trials in the 1980s showing a reduction in breast cancer-specific mortality. However, their effectiveness remains debated and estimates vary. A breast cancer screening program was introduced in 2001 in Flanders, Belgium where high levels of opportunistic screening practices are observed. The effectiveness of this program was estimated by measuring its effect on breast cancer-specific mortality. METHODS: We performed a case-referent study to investigate the effect of participation in the Flemish population-based mammography screening program (PMSP) on breast cancer-specific mortality from 2005 to 2017. A multiple logistic regression model assessed the association between breast cancer-specific death and screening program participation status in the four years prior to (pseudo)diagnosis (yes/no), with adjustment for potential confounders (individual socio-economic position and calendar year of diagnosis) and stratified for age. In addition, we performed different sensitivity analyses. RESULTS: We identified 1571 cases and randomly selected 6284 referents. After adjustment, women who participated in PMSP had a 51 % lower risk of breast cancer-specific mortality compared to those who did not (adjusted odds ratio [aOR] =0.49, 95 % CI: 0.44-0.55). Sensitivity analyses did not markedly change the estimated associations. Correction for self-selection bias reduced the effect size, but the estimate remained significant. CONCLUSION: Our results indicate that in a context of high opportunistic screening rates, participation in breast cancer screening program substantially reduces breast cancer-specific mortality. For policy, these results should be balanced against the potential harms of screening, including overdiagnosis and overtreatment.

Colorectal cancer incidence and survival inequalities among labour immigrants in Belgium during 2004-2013.

Colorectal cancer (CRC) is one of the leading causes of cancer-related morbidity and mortality. We aim to map out differences in CRC incidence and survival between first-generation traditional labour immigrants of Italian, Turkish and Moroccan descent and native Belgians; and assess the contribution of socioeconomic position (SEP) to these differences. Individually-linked data of the 2001 Belgian Census, the Crossroads Bank for Social Security and the Belgian Cancer Registry are used. Age-standardized incidence rates and incidence rate ratios are calculated by country of origin, with and without adjusting for SEP. For CRC patients, 5-year relative survival rates and the relative excess risk for dying within five years after diagnosis are calculated by migrant origin. Lower CRC incidence was observed among immigrants compared to native Belgians, in particular among non-Western immigrants, which could not be explained by SEP. Survival inequalities were less clear, yet, after adjusting for age and stage at diagnosis and educational attainment, we observed a survival advantage among Turkish and Italian immigrant men. Health gains can be made for the native population by adapting lifestyle. The later stage at diagnosis for immigrants is of concern. Barriers regarding screening as perceived by the vulnerable groups should be identified.

Real-World Estimation of First- and Second-Line Treatments for Diffuse Large B-Cell Lymphoma Using Health Insurance Data: A Belgian Population-Based Study.

We determined first- and second-line regimens, including hematopoietic stem cell transplantations, in all diffuse large B cell lymphoma (DLBCL) patients aged ≥20 yr (n = 1,888), registered at the Belgian Cancer Registry (2013-2015). Treatments were inferred from reimbursed drugs, and procedures registered in national health insurance databases. This real-world population-based study allows to assess patients usually excluded from clinical trials such as those with comorbidities, other malignancies (12%), and advanced age (28% are ≥80 yr old). Our data show that the majority of older patients are still started on first-line regimens with curative intent and a substantial proportion of them benefit from this approach. First-line treatments included full R-CHOP (44%), "incomplete" (R-)CHOP (18%), other anthracycline (14%), non-anthracycline (9%), only radiotherapy (3%), and no chemo-/radiotherapy (13%), with significant variation between age groups. The 5-year overall survival (OS) of all patients was 56% with a clear influence of age (78% [20-59 yr] versus 16% [≥85 yr]) and of the type of first-line treatments: full R-CHOP (72%), other anthracycline (58%), "incomplete" (R-)CHOP (47%), non-anthracycline (30%), only radiotherapy (30%), and no chemo-/radiotherapy (9%). Second-line therapy, presumed for refractory (7%) or relapsed disease (9%), was initiated in 252 patients (16%) and was predominantly (71%) platinum-based. The 5-year OS after second-line treatment without autologous stem cell transplantation (ASCT) was generally poor (11% in ≥70 yr versus 17% in <70 yr). An ASCT was performed in 5% of treated patients (n = 82). The 5-year OS after first- or second-line ASCT was similar (69% versus 66%). After adjustment, multivariable OS analyses indicated a significant hazard ratio (HR) for, among others, age (HR 1.81 to 5.95 for increasing age), performance status (PS) (HR 4.56 for PS >1 within 3 months from incidence), subsequent malignancies (HR 2.50), prior malignancies (HR 1.34), respiratory and diabetic comorbidity (HR 1.41 and 1.24), gender (HR 1.25 for males), and first-line treatment with full R-CHOP (HR 0.41) or other anthracycline-containing regimens (HR 0.72). Despite inherent limitations, patterns of care in DLBCL could be determined using an innovative approach based on Belgian health insurance data.

Socio-Economic Position, Cancer Incidence and Stage at Diagnosis: A Nationwide Cohort Study in Belgium.

Background: Socio-economic position is associated with cancer incidence, but the direction and magnitude of this relationship differs across cancer types, geographical regions, and socio-economic parameters. In this nationwide cohort study, we evaluated the association between different individual-level socio-economic and -demographic factors, cancer incidence, and stage at diagnosis in Belgium. Methods: The 2001 census was linked to the nationwide Belgian Cancer Registry for cancer diagnoses between 2004 and 2013. Socio-economic parameters included education level, household composition, and housing conditions. Incidence rate ratios were assessed through Poisson regression models. Stage-specific analyses were conducted through logistic regression models. Results: Deprived groups showed higher risks for lung cancer and head and neck cancers, whereas an inverse relation was observed for malignant melanoma and female breast cancer. Typically, associations were more pronounced in men than in women. A lower socio-economic position was associated with reduced chances of being diagnosed with known or early stage at diagnosis; the strongest disparities were found for male lung cancer and female breast cancer. Conclusions: This study identified population groups at increased risk of cancer and unknown or advanced stage at diagnosis in Belgium. Further investigation is needed to build a comprehensive picture of socio-economic inequality in cancer incidence.

Social Inequalities in Cancer Survival in Belgium: A Population-Based Cohort Study.

BACKGROUND: Socioeconomic status (SES) is an important factor in cancer survival; however, results are heterogeneous and linked to characteristics of the study population and health care system. This population-based cohort study evaluates the association between individual-level socioeconomic and demographic factors and cancer survival for the first time in Belgium. METHODS: From the Belgian Cancer Registry, we identified 109,591 patients diagnosed between 2006 and 2013 with one of eight common cancer types. Information on treatment, socioeconomic parameters, and vital status were retrieved from multiple data sources and linked using a unique personal identification number. The outcome was 5-year observed survival. Associations between survival and socioeconomic and demographic factors were assessed using multivariable Cox proportional-hazard regression models. RESULTS: Lower income, unemployment, and living alone were all associated with worse cancer survival. These associations were most pronounced for certain lifestyle-related cancer types (e.g., head and neck cancers) and those with good to moderate prognosis (e.g., colorectal and female breast cancer). CONCLUSIONS: These results indicate that, despite a comprehensive and nationwide health insurance program in which equity in rights and access to health care are pursued, SES is associated with disparities in cancer survival in Belgium. IMPACT: This population-based study with individual-level socioeconomic information of more than 100,000 patients with cancer identifies patient groups that may be at highest risk for socioeconomic disparities in cancer survival. Reasons behind the observed disparities are multiple and complex and should be further examined. Health policy interventions should consider the observed deprivation gap to plan targeted actions.

Cancer risk among individuals of migrant origin in Belgium during the 2000s - Evidence of migration as a 'cancer risk transition'?

Recent research has shown a generally lower cancer risk and mortality among migrants from less-industrialised country origin. However, while rates are usually lower for 'lifestyle-related' cancers (e.g. breast, prostate, lung, colorectal), they are typically elevated for 'infection-related' ones such as liver and stomach cancer. Although these observations appear in line with the theory of 'migration as a rapid epidemiological transition', changes in cancer risk after migration have yet to be investigated, effectively testing if migration also entails a 'rapid cancer risk transition'. This study therefore examines cancer risk among migrants in Belgium, focusing on colorectal cancer as a typically lifestyle-related cancer on the one hand, and infection-related cancers on the other hand. We subdivide migrant groups of more and less industrialised country origin according to duration of stay, and calculate absolute and relative incidence rates between 2004 and 2013. Our findings corroborate the transition assumptions for men from Turkey and Morocco, but cannot support them for women. Italian male immigrants have an in-between position: their colorectal cancer risk does not differ from that of Belgian men, but infection-related and non-cardia stomach cancer risks are higher and remain so with longer duration of stay. The fact that rates for migrants from the Netherlands and France generally do not differ from those of Belgians further strengthens support for a cancer transition among male migrants. Further examinations should focus on changes in health-related behaviour that can explain persistently low colorectal cancer risks among Turkish and Moroccan migrants and can inform preventive strategies for other population subgroups. Knowledge about the higher non-cardia stomach cancer risk among Turkish, Moroccan, and Italian men can support early detection strategies by primary care providers when patients present with gastric symptoms, especially because this cancer tends to have unfavourable prognosis.

Childhood leukemia near nuclear sites in Belgium: An ecological study at small geographical level.

BACKGROUND: A previous investigation of the occurrence of childhood acute leukemia around the Belgian nuclear sites has shown positive associations around one nuclear site (Mol-Dessel). In the following years, the Belgian Cancer Registry has made data available at the smallest administrative unit for which demographic information exists in Belgium, i.e. the statistical sector. This offers the advantage to reduce the potential misclassification due to large geographical scales. METHODS: The current study performed for the period 2006-2016 uses Poisson models to investigate (i) the incidence of childhood acute leukemia within 20 km around the four Belgian nuclear sites, (ii) exposure-response relationships between cancer incidence and surrogate exposures from the nuclear sites (distance, wind direction frequency and exposure by hypothetical radioactive discharges taking into account historical meteorological conditions). All analyses are carried out at statistical sector level. RESULTS: Higher incidence rate ratios were found for children <15 years (7 cases, RR = 3.01, 95% CI: 1.43;6.35) and children <5 years (< 5 cases, RR = 3.62, 95% CI: 1.35;9.74) living less than 5 km from the site of Mol-Dessel. In addition, there was an indication for positive exposure-response relationships with the different types of surrogate exposures. CONCLUSION: Results confirm an increased incidence of acute childhood leukemia around Mol-Dessel, but the number of cases remains very small. Random variation cannot be excluded and the ecological design does not allow concluding on causality. These findings emphasize the need for more in-depth research into the risk factors of childhood leukemia, for a better understanding of the etiology of this disease.

Assessing the completeness and correctness of the registration of malignant mesothelioma in Belgium.

OBJECTIVES: Malignant mesothelioma (MM) is a rare and aggressive cancer mostly caused by asbestos exposure, and for which the diagnosis is difficult. This study aimed to assess the completeness and correctness of MM registration using 3 independent national databases: the Belgian Cancer Registry (BCR), the population-based mortality statistics (certificates of death, COD), and the Belgian Mesothelioma Registry (BMR). METHODS: The study cohort included all MM reported to the BCR and diagnosed between 2004 and 2012 (n = 2292), all patients reviewed by the pathology commission of the BMR (2004-2012; n = 2019), and COD data for all Belgian citizens (2004-2013). Available data were compared in terms of registered cases, histological diagnosis, performed immunohistochemical (IHC) tests, and IHC test results. RESULTS: Comparison of BCR with BMR registrations showed 94.8% concordant cases. The proportion of MM diagnoses originally reported to BCR with unspecified MM morphology was reduced from 25.8% to less than 1%. RESULTS: from IHC tests were available for 95.3% of concordant MM cases. Different IHC patterns could be distinguished by MM histology. MM cases registered at BCR for which COD mentioned an MM as underlying cause of death represented 76.4% of deceased cases. MM long-term survivors (survival >3 years; 10.9%) were characterised by distinct clinical and biological characteristics. CONCLUSIONS: A comparison of independent Belgian MM registration databases elucidated under-registration and misclassification and revealed possible reasons for observed discordances. Combining all the available information resulted in enhanced completeness and correctness of MM registration in Belgium and allowed for the identification and characterisation of MM long-term survivors.

Real-life treatment practice for malignant pleural mesothelioma in Belgium.

OBJECTIVES: Malignant pleural mesothelioma (MPM) is a rare and aggressive cancer, for which treatment is often limited to palliative combination chemotherapy. Multimodality-therapy, including radical surgery, is largely restricted to clinical trials, leaving its benefit currently unclear. This study aimed to get a comprehensive view on real-world MPM treatment at the Belgian population level, to assess survival and to identify prognostic factors. MATERIALS AND METHODS: The study period covered the incidence years 2004-2012 (N = 1453). Starting from the Belgian Cancer Registry, additional information regarding patient characteristics, diagnosis and treatment was retrieved from multiple data sources. Adjusted cox proportional-hazard regression models using time-dependent covariates were performed to assess survival in relation to treatment patterns and centre volume. RESULTS: Sixty-nine percent of patients underwent tumour-directed treatment, mostly cisplatin-pemetrexed chemotherapy. Radical surgery was mainly performed in younger patients with epithelioid subtype. Centre volume, surgery and chemotherapy showed a positive relation with survival in univariable analyses, but only chemotherapy remained significantly relevant in multivariable analyses. Younger patients, females, and epithelioid subtypes also independently had a better survival. CONCLUSION: This large population-based study provides insights in MPM treatment practice in Belgium. Centre volume and surgery being related to survival in univariable analyses, only chemotherapy remained prognostic after adjustment.