Area-level income disparities in colorectal screening in Canada: evidence to inform future surveillance

Geographical Disparities in Colorectal Cancer in Canada: A Review

PURPOSE OF REVIEW

Colorectal cancer (CRC) is a prominent contributor to cancer-related mortality in Canada. This review paper sheds light on the research conducted in Canada to scrutinize the influence of economicfactors. The review seeks to uncover notable disparities in Colorectal cancer incidence and mortality rate across diverse Canadian populations, including Indigenous communities, rural dwellers, and individuals with lower socioeconomic status (SES).

RECENT FINDINGS

Recent investigations reveal significant disparities in CRC incidence, mortality, and treatment outcomes among various demographic groups in Canada. Indigenous peoples, rural populations, and those with lower SES are particularly vulnerable to these disparities. Access to screening and specialized cancer care is notably limited for these marginalized populations, exacerbating existing health inequities. Furthermore, emerging evidence underscores the potential influence of dietary factors on CRC risk, highlighting the importance of tailored prevention and treatment strategies. The findings underscore the urgent need for targeted interventions aimed at enhancing access to CRC screening and specialized cancer care for disadvantaged populations in Canada. By addressing these disparities, more individuals can undergo timely screening and receive early-stage diagnoses, thereby improving prognosis and ultimately saving lives. However, to effectively bridge these gaps, further research is imperative to elucidate the underlying mechanisms driving these disparities and to identify and implement effective interventions.

Racial and sociodemographic distribution of colorectal cancer screening in Canada: A cross-sectional study

OBJECTIVES

To assess the racial and sociodemographic distribution of colorectal cancer (CRC) screening uptake in Canada, identify disparities, and evaluate the potential predictors and barriers to CRC screening.

METHODS

Data from the 2017 cycle of the Canadian Community Health Survey (CCHS) were analyzed, focusing on individuals aged 50-74 years. CRC screening participation rates were evaluated at both national and provincial levels and across various sociodemographic characteristics. Multivariable logistic regression models were employed to identify predictors and barriers to CRC screening.

RESULTS

Of the 56,950 respondents to the 2017 CCHS, 41.7% (n = 23,727) were between 50 and 74 years of age. The overall CRC screening participation rate was 59.8%, with provinces like Alberta and Manitoba achieving rates of 65.7% and 66.5%, respectively. Significant disparities were observed across socioeconomic, geographical, and racial or ethnic groups. Notably, older adults [AOR 2.41, 95% CI 2.06‒2.83], higher income earners [AOR 1.99, 95% CI 1.77‒2.24], and non-smokers [AOR 1.76, 95% CI 1.55‒2.0] had higher odds of screening, while immigrants and minority ethnic groups, especially South-East Asians [AOR 0.48, 95% CI 0.29‒0.78] and South Asians [AOR 0.65, 95% CI 0.44‒0.95], had lower odds of being up to date with CRC screening. A significant portion of unscreened individuals cited their healthcare provider's perception of the test as unnecessary.

CONCLUSION

While there is promising progress in CRC screening participation rates across Canada, significant disparities persist. Addressing these disparities is crucial for public health. Efforts should focus on enhancing public awareness, facilitating accessibility, and ensuring cultural appropriateness of CRC screening initiatives.

The projected health and economic impact of increased colorectal cancer screening participation among Canadians by income quintile

OBJECTIVES

Disparities in colorectal cancer (CRC) screening uptake by socioeconomic status have been observed in Canada. We used the OncoSim-Colorectal model to evaluate the health and economic outcomes associated with increasing the participation rates of CRC screening programs to 60% among Canadians in different income quintiles.

METHODS

Baseline CRC screening participation rates were obtained from the 2017 Canadian Community Health Survey. The survey participants were categorized into income quintiles using their reported household income and 2016 Canadian Census income quintile thresholds. Within each quintile, the participation rate was the proportion of respondents aged 50-74 who reported having had a fecal test in the past two years. Using the OncoSim-Colorectal model, we simulated an increase in CRC screening uptake to 60% across income quintiles to assess the effects on CRC incidence, mortality, and associated economic costs from 2024 to 2073.

RESULTS

Increasing CRC screening participation rates to 60% across all income quintiles would prevent 69,100 CRC cases and 36,600 CRC deaths over 50 years. The improvement of clinical outcomes would also translate to increased person-years and health-adjusted person-years. The largest impact was observed in the lowest income group, with 22,200 cases and 11,700 deaths prevented over 50 years. Increased participation could lead to higher screening costs ($121 million CAD more per year) and lower treatments costs ($95 million CAD less per year), averaged over the period 2024-2073.

CONCLUSION

Increased screening participation will improve clinical outcomes across all income groups while alleviating associated treatment costs. The benefits of increased participation will be strongest among the lowest income quintile.

Provincial variation in colorectal cancer screening adherence in Canada; evidence from the Canadian Partnership for Tomorrow's Health

Introduction

Although colorectal cancer (CRC) screening program is proven to reduce CRC incidence and mortality, understanding patterns and predictors of suboptimal adherence in screening program requires further investigation in Canada.

Methods

We used self-reported data from five regional cohorts of the Canadian Partnership for Tomorrow's Health (CanPath), namely the BC Generations Project (BCGP), Alberta's Tomorrow Project (ATP), the Ontario Health Study (OHS), Quebec's CARTaGENE, and the Atlantic Partnership for Tomorrow's Health Study (Atlantic PATH). We stratified participants into the following four risk categories: 1) age 50-74 years, 2) family history in a first-degree relative, 3) personal history of chronic inflammatory bowel disease and/or polyps, and 4) co-existence of personal risk and family history. Multivariable logistic regression was used to identify predictors of adherence to the screening guidelines.

Results

Adherence to CRC screening varied considerably between regions, ranging from 16.6% in CARTaGENE to 47.7% in OHS. Compared to the largest cohort OHS, the likelihood of non-adherence to CRC screening was significantly higher in BCGP (OR 1.15, 95% CI 1.11-1.19), the Atlantic PATH (OR 1.90, 95% CI 1.82-1.99) and CARTaGENE (OR 5.10, 95% CI 4.85-5.36). Low physical activity, current smoking, presence of personal risk, family history of CRC significantly reduced the likelihood of adherence to screening recommendations.

Discussion/conclusion

Compared to the national target of ≥ 60% for participation in CRC screening, adherence to regular CRC screening was suboptimal in this cohort of Canadians and varied by region. Further efforts are needed to identify the specific barriers to screening adherence in different provinces and across risk categories.

Neighborhood deprivation and obesity: Sex-specific effects of cross-sectional, cumulative and residential trajectory indicators

Obesity is a long-term health issue that is becoming increasingly prevalent. Very few studies have considered the life course effects of neighborhood characteristics on obesity. In a sample of 35,856 adult participants (representative of the population of the Province of Quebec in Canada), we measured the association between neighborhood deprivation and obesity using logistic modelling on indicators of cross-sectional neighborhood deprivation, cumulative neighborhood deprivation and trajectories of neighborhood deprivation. For cross-sectional exposure, we found that females in our sample had higher odds of being affected by obesity when living in high-deprivation (OR 1.73, CI 1.41-2.13) or medium-deprivation neighborhoods (OR 1.27, CI 1.07-1.51) compared to females living in low-deprivation neighborhoods. Males also had higher odds of being affected by obesity when living in medium or high deprivation. For cumulative exposure to neighborhood deprivation, only females in the second highest category for longitudinal exposure to deprived neighborhoods had significantly higher odds of living with obesity (OR 1.89 CI 1.12-3.19) compared to females in the low cumulative exposure category. Using sequence analysis to determine neighborhood deprivation trajectories for up to 17 years, we found that females with a Deprived upward (OR 1.75 CI 1.10-2.78), an Average downward (OR 1.75 CI 1.08-2.84) or a Deprived trajectory (OR 1.81 CI 1.45-2.86) had higher odds of living with obesity compared to the Privileged trajectory. For males, there were no significant associations. Using trajectory indicators was beneficial to our analyses because this method shows that not only are individuals in low socioeconomic status neighborhoods at the end of their trajectory more susceptible to living with obesity, but so are those exposed to neighborhood deprivation at the beginning of their trajectory. These results could help to more precisely identify individuals at higher risk of developing obesity-related health issues.

Patterns of up-to-date status for colorectal cancer screening in Alberta: a cross-sectional study using survey data

BACKGROUND

Regular screening for colorectal cancer (CRC) reduces its mortality. We explored patterns of use of different CRC screening modalities and quantified the association between having a regular primary care provider and being up to date for CRC screening in a community-based population in Alberta, Canada.

METHODS

We conducted a cross-sectional study of adults between 50 and 74 years of age in Alberta, using Canadian Community Health Survey data (2015-2016). We defined being up to date for CRC screening as having completed a fecal occult blood test (FOBT) or fecal immunochemical test (FIT) within the previous 2 years, or having a colonoscopy or sigmoidoscopy in the previous 5 years before the survey. We analyzed data using multivariable logistic regression models.

RESULTS

Of 4600 surveyed adults, 62.6% were up to date for CRC screening, with 45.1% having completed a FIT or FOBT (45.1%), and 34.1% having undergone a colonoscopy or sigmoidoscopy. The adjusted odds ratio of being up to date for CRC screening was 0.25 (95% confidence interval 0.17-0.38) and the absolute probability of being up to date for CRC screening was 34.4% lower for adults who had no regular primary care provider, compared with those who had. This pattern was observed in both male and female subgroups.

INTERPRETATION

Our findings suggest a suboptimal uptake of CRC screening overall in Alberta, with high disparity between adults with and without a regular primary care provider. The use of customized, multicomponent intervention strategies that are shown to be effective in increasing participation in CRC screening may address this issue.

Socioeconomic inequalities in colorectal cancer incidence in Canada: trends over two decades

PURPOSE

Colorectal cancer is the third most commonly diagnosed cancer in Canada. This study aimed to measure and examine trends in socioeconomic inequalities in the incidence of colorectal cancer in Canada.

METHODS

This study is a time trend ecological study based on Canadian Census Division level data constructed from the Canadian Cancer Registry, Canadian Census of Population, and National Household Survey. We assessed trends in income and education inequalities in colorectal cancer incidence in Canada from 1992 to 2010. The age-standardized Concentration index ([Formula: see text]), which measures inequality across all socioeconomic groups, was used to quantify socioeconomic inequalities in colorectal cancer incidence in Canada.

RESULTS

The average crude colorectal cancer incidence was found to be 61.52 per 100,000 population over the study period, with males having a higher incidence rate than females (males: 66.98; females: 56.25 per 100,000 population). The crude incidence increased over time and varied by province. The age-standardized C indicated a higher concentration of colorectal cancer incidence among lower income and less-educated neighborhoods in Canada. Income and education inequalities increased over time among males.

CONCLUSION

The concentration of colorectal cancer incidence in low socioeconomic neighborhoods in Canada has implications for primary prevention and screening.

Cross-sectional adherence with the multi-target stool DNA test for colorectal cancer screening in a large, nationally insured cohort

PURPOSE

Colorectal cancer (CRC) is the second most deadly cancer in the USA. Early detection can improve CRC outcomes, but recent national screening rates (62%) remain below the 80% goal set by the National Colorectal Cancer Roundtable. Multiple options are endorsed for average-risk CRC screening, including the multi-target stool DNA (mt-sDNA) test. We evaluated cross-sectional mt-sDNA test completion in a population of commercially and Medicare-insured patients.

METHODS

Participants included individuals ages 50 years and older with commercial insurance or Medicare, with a valid mt-sDNA test shipped by Exact Sciences Laboratories LLC between January 1, 2018, and December 31, 2018 (n = 1,420,460). In 2020, we analyzed cross-sectional adherence, as the percent of successfully completed tests within 365 days of shipment date.

RESULTS

Overall cross-sectional adherence was 66.8%. Adherence was 72.1% in participants with Traditional Medicare, 69.1% in participants with Medicare Advantage, and 61.9% in participants with commercial insurance. Adherence increased with age: 60.8% for ages 50-64, 71.3% for ages 65-75, and 74.7% for ages 76 + years. Participants with mt-sDNA tests ordered by gastroenterologists had a higher adherence rate (78.3%) than those with orders by primary care clinicians (67.2%). Geographically, adherence rates were highest among highly rural patients (70.8%) and ordering providers in the Pacific region (71.4%).

CONCLUSIONS

Data from this large, national sample of insured patients demonstrate high cross-sectional adherence with the mt-sDNA test, supporting its role as an accepted, noninvasive option for average-risk CRC screening. Attributes of mt-sDNA screening, including home-based convenience and accompanying navigation support, likely contributed to high completion rates.

The impact of socioeconomic status on stage at presentation, receipt of diagnostic imaging, receipt of treatment and overall survival in colorectal cancer patients

Socioeconomic factors influence patterns of care in colorectal cancer. Our study investigates the impact of socioeconomic status (SES) on stage at presentation, receipt of diagnostic imaging, receipt of treatment and overall survival (OS) in a universal healthcare system. The Ontario Cancer Registry (OCR) was accessed to identify a cohort of patients diagnosed with colorectal adenocarcinoma from 2007 to 2016 in Ontario, Canada. SES was measured using median neighborhood income divided into quintiles (Q1-Q5; Q1 = lowest income). Logistic regression analyses were used to evaluate stage, imaging and treatment. Cox proportional hazards models were used to evaluate OS. All endpoints were adjusted for demographics and comorbidities with OS models also adjusting for stage, imaging and treatment. In total, 39 802 colon and 13 164 rectal patients were identified. Lower SES was associated with advanced stage at presentation in both cohorts (Q1 vs Q5: Colon odds ratio [OR] = 1.08, P = .046, rectal OR = 1.25, P < .0001). Lower SES colon patients were less likely to receive adjuvant oxaliplatin (Q1 vs Q5: OR = 0.78, P < .001) and all palliative chemotherapies studied including oxaliplatin (Q1 vs Q5: OR = 0.60, P < 0.0001), irinotecan (Q1 vs Q5: OR = 0.65, P < .0001), bevacizumab (Q1 vs Q5: OR = 0.70, P < .001), cetuximab (Q1 vs Q5: OR = 0.40, P = .0053) and panitumumab (Q1 vs Q5: OR = 0.54, P = .0036). In rectal patients, lower SES was associated with decreased receipt of rectal cancer resection for stages I-III (Q1 vs Q5: OR = 0.78, P < .001), adjuvant oxaliplatin (Q1 vs Q5: OR = 0.72, P = .0020) and palliative chemotherapies including oxaliplatin (Q1 vs Q5: OR = 0.59, P < .001), irinotecan (Q1 vs Q5: OR = 0.53, P < .001) and bevacizumab (Q1 vs Q5: OR = 0.71, P = .046). All survival models identified poorer OS for lower SES patients (total colorectal; Q1 vs Q5: Hazard ratio [HR] = 1.25, P < .0001). These findings suggest disparities persist even within universal healthcare.

Factors associated with colorectal cancer screening in a peer-counseling intervention study in partnership with African American churches

Colorectal cancer (CRC) mortality is 47% higher in African American men and 34% higher in African American women compared to non-Hispanic white men and women. This analysis assessed factors associated with CRC screening among 163 African American participants of a peer-counseling intervention study (2016-2018). In a one-group pre/post-test pilot study, trained Community Health Advisors (CHAs) at 9 African American churches in Los Angeles (LA) promoted CRC screening via one-on-one counseling, print materials and telephone reminder calls. Participants completed telephone surveys 3-6 months after the intervention. We fit bivariate and multivariate mixed effects logistic regression models to assess correlates, including participants' demographic characteristics, access to care, cancer-related knowledge and attitudes and receipt of CHA counseling of (1) discussion of CRC screening with provider and (2) receipt of CRC screening during follow-up. After controlling for gender and education, receipt of CHA counseling (OR 3.77) was significantly associated with discussing CRC screening with a provider during follow-up but not with CRC screening. Instead, a routine check-up in the past 12 months (OR 4.47) and discussion of CRC screening with a provider (OR 3.07) were significantly associated with CRC screening during follow-up. Residence in South LA (OR 0.38) was significantly associated with lack of CRC screening. Findings confirm the important role of health care providers and suggest that residence in South LA constitutes an additional barrier to CRC screening. Further research and additional resources are needed to address disparities in the uptake of CRC screening among African Americans, especially in South LA.

Associations between area-level deprivation, rural residence, physician density, screening policy and late-stage colorectal cancer in Canada

BACKGROUND

Important social disparities in colorectal screening exist in Canada. Few studies have assessed disparities further along the cancer control continuum. Here we assess the associations between social and material deprivation, physician density, rural residence, and the absence of provincial mail-based screening programs and colorectal cancer (CRC) stage at diagnosis.

METHODS

Colorectal cancer cases and stage data ("local or regional" if stage 0, I, or II, "late" if stage III or IV) were obtained through the Canadian Cancer Registry (2011-2015, N = 54,745). Cases were linked to 2006 Canadian Census Dissemination Area-level data on rural/urban status, exposure to a provincial mail-based screening program, and social and material deprivation (Pampalon Index quintile groups); and to Scott's Medical Database 2011 physician density data (<7 vs. ≥ 7/10,000). Age, sex, and predictor-adjusted Generalized estimating equation (GEE) Poisson models were used to determine independent associations between predictors and late-stage at diagnosis.

RESULTS

Half of CRC cases are diagnosed at stage III or IV (51 %), with younger age groups experiencing higher late-stage prevalence (57 % among those aged 18-49). The covariate-adjusted late-stage prevalence was 2-percentage points higher in most materially- and socially-deprived areas (95 % CI: 1 %, 4 %, in both, respectively) and in provinces with no mail-based screening programs (95 % CI: 1 %, 2 %). No significant differences were observed according to rural residence or physician density.

CONCLUSIONS

Social disparities in late-stage CRC diagnosis are modest. Continued surveillance of these disparities may be warranted as provinces continue to promote early cancer detection through screening, and stage distributions may change overtime.

Why are we organizing another costing supplement in Current Oncology?

Why are we publishing another costing supplement in Current Oncology? [...]

The Role of Access to a Regular Primary Care Physician in Mediating Immigration-Based Disparities in Colorectal Screening: Application of Multiple Mediation Methods

BACKGROUND

Colorectal cancer screening participation is lower among recent immigrants than among Canadian-born individuals. We assessed whether this screening disparity is mediated by access to regular primary care physicians (PCP).

METHODS

Pooling years 2003 to 2014 of the Canadian Community Health Survey, lifetime screening in respondents aged 50 to 75 years of age who immigrated in the previous 10 years (n = 1,067) was compared with Canadian-born respondents (N = 102,366). Regression- and inverse probability weighting-based methods were used to estimate the total effect (TE) and controlled direct effect (CDE) of recent immigration on never having received either a stool- or endoscopic-based screening test. The proportion of the TE that would be eliminated if all had a PCP was computed using these estimates [proportion eliminated (PE) = (TE - CDE)/(TE - 1)]. Analyses were stratified by visible minority status and adjusted for income, rurality, age, sex, marital status, education, and exposure to a provincially organized colorectal screening program.

RESULTS

The prevalence of never having been screened was 71% and 57% in visible minority and white recent immigrants, respectively, and 46% in white Canadian-born respondents. If all had regular PCPs, there would be no reduction in the screening inequality between white recent immigrants and Canadian-born (null PE), and the inequality between visible minority immigrants and white Canadian-born may increase by 6% to 13%.

CONCLUSIONS

Ensuring all have regular PCPs may lead to greater screening gains among Canadian-born than recent immigrants.

IMPACT

Improving access to PCPs may increase colorectal screening overall, but not reduce immigration-based disparities screening. Alternative interventions to reduce this disparity should be explored.