Geographical variation and factors associated with colorectal cancer mortality in a universal health care system

Colorectal Cancer Incidence in Iran Based on Sex, Age, and Geographical Regions: A Study of 2014-2017 and Projected Rates to 2025

BACKGROUND

While there has been extensive research on colorectal cancer (CRC) incidence and its associated factors in Iran, a significant gap exists in studies predicting its future trends. Our study aimed to thoroughly report CRC incidence across Iran from 2014 to 2017, by sex, age, and geographical regions, and provide a projection for 2025.

METHODS

This retrospective study utilized data from the Iranian National Population-based Cancer Registry (INPCR). Patients with the International Classification of Diseases for Oncology, 3rd Edition (ICD-O-3) codes C18 to C21 were included. The age-standardized incidence rate (ASR), was calculated per 100000 individuals annually, and crude incidence rates were retrieved for various demographic groups and years.

RESULTS

Between 2014 and 2017, a total of 43580 new CRC cases (55.96% males) were registered. Men exhibited an ASR of 134.45, while women's ASR was 94.85. The highest ASRs were observed in Tehran, Qom, and Ilam (18.99, 18.26, and 18.06, respectively). Incidence rates surpassed 20 after age 50 for both genders, reaching their peak within the 80-84 age group. Adenocarcinoma was the most frequent histological type of CRC in nearly all provinces. Case numbers and ASRs are projected to continuously rise until 2025, with a predominance of male cases.

CONCLUSION

The anticipated increase in CRC incidence in Iran emphasizes the need for additional studies to better identify risk factors. Furthermore, implementing screening programs is recommended for individuals at a higher risk of CRC, including men, the elderly population, and those residing in regions with a notable prevalence of CRC.

Geographical variations in long term colorectal cancer outcomes in England: a contemporary population analysis revealing the north-south divide in colorectal cancer survival

BACKGROUND

Regional variations in healthcare outcomes in England have been historically reported. This study analyses the variations in long term colorectal cancer survival across different regions in England.

METHODS

Relative survival analysis of population data obtained from all cancer registries in England between 2010 and 2014.

RESULTS

Totally, 167,501 patients were studied. Regions in the southern England had better outcomes with Southwest and Oxford registries having 63.5 and 62.7% 5 year relative survival. In contrast, Trent and Northwest cancer registries had 58.1% relative survival (p < 0.01). The regions in the north fared below the national average. The survival outcomes reflected socio-economic deprivation status, the best performing regions in the south having low levels of deprivation (5.3 and 6.5% having maximum deprivation in Southwest and Oxford, respectively). The regions with worst long term cancer outcomes had high levels of deprivation with 25% and 17% having high levels of deprivation in Northwest and Trent regions.

CONCLUSION

There are significant variations in long term colorectal cancer survival between different regions in England, southern England had better relative survival when compared with the northern regions. Disparities in socio-economic depravation status in different regions may be associated with worse colorectal cancer outcomes.

Impact of Socioeconomic Status on Cancer Incidence Risk, Cancer Staging, and Survival of Patients with Colorectal Cancer under Universal Health Insurance Coverage in Taiwan

This study examined the impact of socioeconomic status on colorectal cancer risk, staging, and survival under the National Health Insurance (NHI) system in Taiwan. Monthly salary and education level were used as measures of socioeconomic status to observe the risk of colorectal cancer among individuals aged 40 years or above in 2006-2015 and survival outcomes of patients with colorectal cancer until the end of 2016. Data from 286,792 individuals were used in this study. Individuals with a monthly salary ≤Q1 were at a significantly lower incidence risk of colorectal cancer than those with a monthly salary >Q3 (HR = 0.80, 95% CI = 0.74-0.85), while those with elementary or lower education were at a significantly higher risk than those with junior college, university, or higher education (HR = 1.18, 95% CI = 1.06-1.31). The results show that socioeconomic status had no significant impact on colorectal cancer stage at diagnosis. Although salary was not associated with their risk of mortality, patients with colorectal cancer who had elementary or lower education incurred a significantly higher risk of mortality than those who had junior college, university, or higher education (HR = 1.39, 95% CI = 1.07-1.77). Education level is a significant determinant of the incidence risk and survival in patients with colorectal cancer, but only income significantly impacts incidence risk.

Geographical variation and factors associated with gastric cancer in Manitoba

Objectives

We investigated the spatial disparities and factors associated with gastric cancer (GC) Incidence in Manitoba.

Methods

We combined information from Manitoba Cancer registry and Census data to obtain an age-sex adjusted relative risk (IRR) of GC incidence. We geocoded the IRR to the 96 regional health authority districts (RHADs) using the postal code conversion file (PCCF). Bayesian spatial and spatio-temporal Poisson regression models were used for the analysis.

Results

Adjusting for the effect of socio-economic score index (SESI), Indigenous, and immigrant population, 25 districts with high overall GC risk were identified. One unit increase in SESI was associated with reduced risk of cardia GC (CGC) by 14% (IRR = 0.859; 95% CI: 0.780–0.947) and the risk of non-cardia GC (NCGC) by approximately 10% (IRR = 0.898; 95% CI: 0.812–0.995); 1% increase in regional Indigenous population proportion reduced the risk of CGC by 1.4% (IRR = 0.986; 95% CI: 0.978–0.994). In the analysis stratified by sex, one unit increase in SESI reduced the risk of CGC among women by 26.2% (IRR = 0.738; 95% CI: 0.618–0.879), and a 1% increase in Indigenous population proportion reduced the risk of CGC among women by 1.9% (IRR = 0.981; 95% CI: 0.966–0.996).

Conclusion

Our results support a significant association between SESI and NCGC. We report regional variation of GC IRR and a varying temporal pattern across the RHADs. These results could be used to prioritize interventions for regions with high and progressive risk of GC.

Canadian Colorectal Cancer Screening Guidelines: Do They Need an Update Given Changing Incidence and Global Practice Patterns?

Colorectal cancer (CRC) is the third most commonly diagnosed cancer and second leading cause of cancer death in Canada. Organized screening programs targeting Canadians aged 50 to 74 at average risk of developing the disease have contributed to decreased rates of CRC, improved patient outcomes and reduced healthcare costs. However, data shows that recent incidence reductions are unique to the screening-age population, while rates in people under-50 are on the rise. Similar incidence patterns in the United States prompted the American Cancer Society and U.S. Preventive Services Task Force to recommend screening begin at age 45 rather than 50. We conducted a review of screening practices in Canada, framing them in the context of similar global health systems as well as the evidence supporting the recent U.S. recommendations. Epidemiologic changes in Canada suggest earlier screening initiation in average-risk individuals may be reasonable, but the balance of costs to benefits remains unclear.

Premature mortality of gastrointestinal cancer in Iran: trends and projections 2001-2030

BACKGROUND

The present study was conducted to determine the trend and projection of premature mortality from gastrointestinal cancers (GI cancers) at national and subnational levels in Iran.

METHODS

Employing the data obtained from Iranian Death Registry System (DRS) and population data from census, the mortality rates of GI cancers was calculated among 30-70 age groups. The trends of esophageal, colon and rectum, gallbladder, pancreases, stomach, and liver cancer premature mortalities were estimated and projected at the national and subnational levels from 2001 to 2030. Then, Spatio-temporal model was used to project spatial and temporal correlations.

RESULTS

The overall mortality rate of GI cancers was higher in males than in females, indicating 6.1, 3.9 and 3.9% per 100,000 individuals among males in 2001, 2015 and 2030 respectively and 3.8, 3.1 and 3.7 per 100,000 individuals among females in the same time-frame. The overall mortality rate of GI cancers in males was decreasing until 2015 and will remain stationary into 2030; however, the rate will be increasing among females in both time-frames. Also, there was a considerable variation in the mortality trends of different cancers. Pancreatic, gallbladder, and liver cancers were shown to have an increasing trend while a drop was observed in the mortality rates of stomach, colon and rectum, and esophageal cancers.

CONCLUSION

Variation of GI cancers patterns and trends around the country indicated that a more comprehensive control plan is needed to include the predicted variations.

Current State of Geospatial Methodologic Approaches in Canadian Population Oncology Research

Geospatial analyses are increasingly used in population oncology. We provide a first review of geospatial analysis in Canadian population oncology research, compare to international peers, and identify future directions. Geospatial-focused peer-reviewed publications from 1992-2020 were compiled using PubMed, MEDLINE, Web of Science, and Google Scholar. Abstracts were screened for data derived from a Canadian cancer registry and use of geographic information systems. Studies were classified by geospatial methodology, geospatial unit, location, cancer site, and study year. Common limitations were documented from article discussion sections. Our search identified 71 publications using data from all provincial and national cancer registries. Thirty-nine percent (N = 28) were published in the most recent 5-year period (2016-2020). Geospatial methodologies included exposure assessment (32.4%), identifying spatial associations (21.1%), proximity analysis (16.9%), cluster detection (15.5%), and descriptive mapping (14.1%). Common limitations included confounding, ecologic fallacy, not accounting for residential mobility, and small case/population sizes. Geospatial analyses are increasingly used in Canadian population oncology; however, efforts are concentrated among a few provinces and common cancer sites, and data are over a decade old. Limitations were similar to those documented internationally, and more work is needed to address them. Organized efforts are needed to identify common challenges, develop leading practices, and identify shared priorities.

Dietary intake of vitamin B12 in relation to diet and lifestyle characteristics in a population at high risk for colorectal cancer

OBJECTIVE

Besides irreplaceable role in health, vitamin B₁₂ is proposed to have cytoprotective role in colorectal cancer (CRC). So far, studies are inconclusive on the role dietary intake of vitamin B₁₂ has in CRC. The aim of this study was to determine whether total dietary intake of vitamin B₁₂ and contribution from its food sources relates to a low-risk diet and lifestyle in a population at high risk for CRC.

METHODS

An observational study on 200 healthy adults from Eastern Croatia was conducted during April-May 2013. A typical diet of this population in this region is characterized with all known major dietary risk factors for CRC placing the population at high risk for CRC, yet the incidence of CRC remains relatively low.

RESULTS

Diet and lifestyle characteristics of 52.2% of participants can be classified as the high-risk for CRC. Women, people in lower BMI category, and urban residents have significantly lower risk of the high-risk diet and lifestyle. Higher intake of vitamin B₁₂ shows positive association with the low-risk diet and lifestyle. Intake of vitamin B₁₂ from milk, dairy and fish represent independent factors for the low-risk diet and lifestyle in this population at high-risk for CRC.

CONCLUSIONS

Higher intake of vitamin B₁₂, especially intake from milk, dairy and fish are associated with the low-risk diet and lifestyle in a population at high risk for CRC. Further studies should focus on interplay between vitamin B₁₂ and other nutrients that share the same food sources to elucidate their role in the aetiology and pathology of CRC.

Alberta Family Physician Electronic Endoscopy study: Quality of 1769 colonoscopies performed by rural Canadian family physicians

OBJECTIVE

To determine whether rural FP colonoscopists in Alberta are achieving benchmarks in colonoscopy quality.

DESIGN

Prospective, multicentre observational study.

SETTING

Alberta.

PARTICIPANTS

Nine FP colonoscopists.

MAIN OUTCOME MEASURES

Proportion of successful cecal intubations; proportion of patients aged 50 and older with pathologically confirmed adenomas; mean number of adenomas per colonoscopy; and serious adverse events related to colonoscopy.

RESULTS

In this 6-month study, 9 rural FPs in Alberta performed 1769 colonoscopies. Overall, all key colonoscopy quality benchmarks were met or exceeded. The proportion of successful cecal intubations was 97.9% (95% CI 97.2% to 98.6%). The proportion of male and female patients aged 50 and older whose first-time colonoscopy results revealed an adenoma was 67.4% (95% CI 62.4% to 72.7%) and 51.1% (95% CI 45.5% to 56.7%), respectively. There were 120 adenomas, 36 advanced adenomas, and 1 colon cancer case per 100 colonoscopies. There were 2 postpolypectomy bleeds and no other serious complications.

CONCLUSION

Alberta rural FP colonoscopists are meeting benchmarks in colonoscopy quality. Ongoing electronic collection of endoscopy quality markers should be encouraged. Supporting and training rural FPs who perform endoscopy might help alleviate current wait times and improve access for rural Canadian patients.

Differences in colorectal cancer screening rates across income strata by levels of urbanization: results from the Canadian Community Health Survey (2013/2014)

OBJECTIVE

Canadian colorectal cancer screening rates differ across income strata. In the United States, disparities across income strata worsen in rural areas. In Canada, differences in screening across income strata have not been explored by levels of urbanization. This project aimed to estimate up-to-date colorectal cancer (UTD-CRC) screening across income strata by levels of urbanization.

METHODS

Data from the Canadian Community Health Survey (2013/2014) were used to estimate the prevalence of UTD-CRC screening by income quintiles for Canadians aged 50-74 years. UTD-CRC screening was defined as fecal occult blood testing within 2 years or colonoscopy/sigmoidoscopy within 10 years before the survey. Levels of urbanization were defined per Statistics Canada Metropolitan Influenced Zone classifications. Weighted proportions of UTD-CRC screening were calculated and logistic regression was used to assess the effect of income by levels of urbanization.

RESULTS

Self-reported UTD-CRC screening prevalence among Canadians was 52.0%. UTD-CRC screening rates by income ranged from 47.8% (Q1-low) to 54.0% (Q5-high). Across all levels of urbanization, higher income was associated with increased odds of UTD-CRC screening compared to the lowest income quintile (Urban-OR_Q5 = 1.49, 95% CI 1.17-1.89; Rural-OR_Q5 = 1.42, 95% CI 1.02-1.99; Remote-OR_Q5 = 1.54, 95% CI 1.02-2.31). Higher education (OR_{post-secondary} = 1.30, 95% CI 1.14-1.49), increasing age (OR_70-74 = 2.88, 95% CI 2.39-3.47), and not identifying as an immigrant (OR = 1.45, 95% CI 1.19-1.75) were associated with an increased odds of UTD-CRC screening.

DISCUSSION

Half of Canadians report UTD-CRC screening but across levels of urbanization, higher income was associated with higher screening rates. Efforts are needed to understand and address inequities, particularly among low-income populations.

Geographic variation and factors associated with colorectal cancer incidence in Manitoba

OBJECTIVES

Although individuals living in areas with lower household income have been shown to have higher rates of mortality from colorectal cancer (CRC), findings on the effect of income on CRC incidence in countries with universal health care have been inconsistent. There are limited data from Canada. We investigated the geographic variation and factors associated with CRC incidence in Manitoba, a central Canadian province.

METHODS

The Manitoba Cancer Registry and Manitoba Health population registry were used to determine age-sex-standardized CRC incidence rates between 1985 and 2012, which were geocoded to 498 small geographic areas (SGAs). The 2001 Canadian Census was used to determine the socio-demographic characteristics of the SGAs. Bayesian spatial Poisson modelling was used to assess geographic variation and factors associated with CRC incidence.

RESULTS

CRC incidence in SGAs ranged from 11 to 1026 per 100 000 population per year. Importantly, in the fully adjusted model there was no significant association between either average household income or proportion of recent immigrants in the SGAs and CRC incidence. Individuals living in urban areas had an overall lower CRC incidence (incidence rate ratio: 0.76; 95% credible interval: 0.58-0.98).

CONCLUSIONS

In a province with a universal health care system, our study suggests there are no disparities in CRC incidence by socio-economic level of the areas of residence. Rural areas should be a focus of CRC reduction initiatives in Manitoba. Similar analysis in other jurisdictions should be performed to evaluate the effect of the characteristics of SGAs on CRC incidence in different settings and target some of the efforts to reduce CRC burden.

Geographic distribution of the incidence of colorectal cancer in Iran: a population-based study

OBJECTIVES

Colorectal cancer (CRC) is the third most common cancer and the fourth most common cause of cancer death in the world. The aim of this study was to investigate the provincial distribution of the incidence of CRC across Iran.

METHODS

This epidemiologic study used data from the National Cancer Registry of Iran and the Center for Disease Control and Prevention of the Ministry of Health and Medical Education of Iran. The average annual age-standardized rate (ASR) for the incidence of CRC was calculated for each province.

RESULTS

We found that adenocarcinoma (not otherwise specified) was the most common histological subtype of CRC in males and females, accounting for 81.91 and 81.95% of CRC cases, respectively. Signet ring cell carcinoma was the least prevalent subtype of CRC in males and females and accounted for 1.5 and 0.94% of CRC cases, respectively. In patients aged 45 years or older, there was a steady upward trend in the incidence of CRC, and the highest ASR of CRC incidence among both males and females was in the age group of 80-84 years, with an ASR of 144.69 per 100,000 person-years for males and 119.18 per 100,000 person-years for females. The highest incidence rates of CRC in Iran were found in the central, northern, and western provinces. Provinces in the southeast of Iran had the lowest incidence rates of CRC.

CONCLUSIONS

Wide geographical variation was found in the incidence of CRC across the 31 provinces of Iran. These variations must be considered for prevention and control programs for CRC, as well as for resource allocation purposes.

Family physician access to and wait times for cancer diagnostic investigations: Regional differences among 3 provinces

OBJECTIVE

To examine provincial and regional differences in FPs' direct access to cancer diagnostic investigations and advice from other specialists regarding investigations and referrals, and to explore FPs' perceptions about wait times for diagnostic investigations and receipt of results.

DESIGN

A cross-sectional, online survey.

SETTING

British Columbia, Manitoba, and Ontario.

PARTICIPANTS

A sample of FPs from participating provinces.

MAIN OUTCOME MEASURES

Direct FP access to various diagnostic investigations and advice from other specialists regarding investigations and referrals; FPs' perceptions about wait times for diagnostic investigations ordered directly; and FPs' perceptions about wait times for results.

RESULTS

A total of 1054 surveys were completed by FPs from British Columbia (n = 229), Manitoba (n = 228), and Ontario (n = 597). Distance from a cancer centre was not significantly associated with direct access to or wait times for diagnostic investigations for most of the investigations studied; however, provincial differences were observed. Family physicians in Manitoba and British Columbia were 30% to 45% less likely to report having direct access to endoscopy and some imaging investigations compared with FPs in Ontario. Family physicians in Manitoba and British Columbia were also at increased odds of waiting longer than 12 weeks for endoscopy investigations and longer than 4 weeks for imaging investigations compared with FPs in Ontario. Most FPs reported wait times of less than 2 weeks for imaging results; however, the proportion of FPs who waited longer than 2 weeks for colonoscopy results ranged from 15% in Ontario to 96% in British Columbia.

CONCLUSION

Given the disparities observed among provinces, there is an opportunity for provinces to learn from one another to improve direct access to and shorten wait times for diagnostic investigations. This in turn has the potential to shorten the primary care interval for cancer diagnostic assessment.

Managing Matajoosh: determinants of first Nations' cancer care decisions

BACKGROUND

Accessing cancer treatment requires First Nation peoples living in rural and remote communities to either commute to care, or to relocate to an urban centre for the length or part of the treatment. While Canadians living in rural and remote communities must often make difficult decisions following a cancer diagnosis, such decisions are further complicated by the unique policy and socio-historical contexts affecting many First Nation peoples in Canada. These contexts often intersect with negative healthcare experiences which can be related to jurisdictional confusion encountered when seeking care. Given the rising incidence of cancer within First Nation populations, there is a growing potential for negative health outcomes.

METHODS

The analysis presented in this paper focuses on the experience of First Nation peoples' access to cancer care in the province of Manitoba. We analyzed policy documents and government websites; interviewed individuals who have experienced relocation (N = 5), family members (N = 8), healthcare providers and administrators (N = 15).

RESULTS

Although the healthcare providers (social workers, physicians, nurses, patient navigators, and administrators) we interviewed wanted to assist patients and their families, the focus of care remained informed by patients' clinical reality, without recognition of the context which impacts and constrains access to cancer care services. Contrasting and converging narratives identify barriers to early diagnosis, poor coordination of care across jurisdictions and logistic complexities that result in fatigue and undermine adherence. Providers and decision-makers who were aware of this broader context were not empowered to address system's limitations.

CONCLUSIONS

We argue that a whole system's approach is required in order to address these limitations.

Regional variations in cancer survival: Impact of tumour stage, socioeconomic status, comorbidity and type of treatment in Norway

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.

Socioeconomic differentials and mortality from colorectal cancer in large cities in Brazil

The objective of this study was to compare the mortality pattern of colorectal cancer according to the social development profile of the large Brazilian cities. This was an ecological study that used as units of analysis Brazilian municipalities that were considered to be large (i.e. over 100,000 inhabitants). The social indicators adopted were obtained from the Atlas of Human Development in Brazil. Mortality data came from the Mortality Information System (MIS), represented by codes C18, C19, and C20. For data analysis, municipalities were characterised according to the indicator profile used by multivariate classification cluster analysis. It was observed that the Southeast, South, and Midwest regions concentrated over 90% of cities in the group of more developed municipalities, while the North and Northeast regions were represented by 60% of cities in the group of less developed municipalities. The mortality pattern of colorectal cancer in both groups was different, with a higher average mortality rate from colorectal cancer for populations living in cities from the more developed group (p = 0.02). The mortality rate from this cancer was shown to be directly proportional to the Municipal Human Developlemnt Index (MHDI) and inversely proportional to the inequality indicator (p < 0.001); therefore the highest means were observed among the municipalities with better socioeconomic conditions. It is important to consider social disparities to ensure equity in healthcare policy management.

Longitudinal Rates of Colon Cancer Screening Use in Winnipeg, Canada: The Experience of a Universal Health-Care System with an Organized Colon Screening Program

OBJECTIVES

We examined trends in colorectal cancer (CRC) screening (fecal occult blood test (FOBT), colonoscopy, and flexible sigmoidoscopy (FS)) and differences in CRC screening by income in a population with an organized CRC screening program and universal health-care coverage.

METHODS

Individuals who had an FOBT, colonoscopy, or FS were identified from the provincial Physician Claims database and the population-based colon cancer screening registry. Trends in age-standardized rates were determined. Logistic regression was performed to explore the association between CRC screening and income quintiles by year.

RESULTS

Up-to-date CRC screening (FOBT, colonoscopy, or FS) increased over time for men and women, all age groups, and all income quintiles. Up-to-date CRC screening was very high among 65- to 69- and 70- to 74-year-olds (70% and 73%, respectively). There was a shift toward the use of an FOBT for CRC screening for individuals in the lower income quintiles. The disparity in colonoscopy/FS coverage by income quintile was greater in 2012 than in 1995. Overall, there was no reduction in disparities by income in up-to-date CRC screening nor did the rate of increase in up-to-date CRC screening or FOBT use change after the introduction of the organized provincial CRC screening program.

CONCLUSIONS

CRC screening is increasing over time for both men and women and all age groups. However, a disparity in up-to-date CRC screening by income persisted even with an organized CRC screening program in a universal health-care setting.

Geographical variation in the incidence of childhood leukaemia in Manitoba

BACKGROUND

Identification of geographical areas and ecological factors associated with higher incidence of childhood leukaemias can direct further study for preventable factors and location of health services to manage such individuals.

AIM

The aim of this study was to describe the geographical variation and the socio-demographic factors associated with childhood leukaemia in Manitoba.

METHODS

Information on childhood leukaemia incidence between 1992 and 2008 was obtained from the Canadian Cancer Registry and the socio-demographic characteristics for the area of residence from the 2006 Canadian Census. Bayesian spatial Poisson mixed models were used to describe the geographical variation of childhood leukaemia and to determine the association between childhood leukaemia and socio-demographic factors.

RESULTS

The south-eastern part of the province had a higher incidence of childhood leukaemia than other parts of the province. In the age and sex-adjusted Poisson regression models, areas with higher proportions of visible minorities and immigrant residents had higher childhood leukaemia incidence rate ratios. In the saturated Poisson regression model, the childhood leukaemia rates were higher in areas with higher proportions of immigrant residents. Unemployment rates were not a significant factor in leukaemia incidence.

CONCLUSION

In Manitoba, areas with higher proportions of immigrants experience higher incidence rates of childhood leukaemia. We have identified geographical areas with higher incidence, which require further study and attention.

Colon cancer care and survival: income and insurance are more predictive in the USA, community primary care physician supply more so in Canada

BACKGROUND

Our research group advanced a health insurance theory to explain Canada's cancer care advantages over America. The late Barbara Starfield theorized that Canada's greater primary care-orientation also plays a critically protective role. We tested the resultant Starfield-Gorey theory by examining the effects of poverty, health insurance and physician supplies, primary care and specialists, on colon cancer care in Ontario and California.

METHODS

We analyzed registry data for people with non-metastasized colon cancer from Ontario (n = 2,060) and California (n = 4,574) diagnosed between 1996 and 2000 and followed to 2010. We obtained census tract-based socioeconomic data from population censuses and data on county-level physician supplies from national repositories: primary care physicians, gastroenterologists and other specialists. High poverty neighborhoods were oversampled and the criterion was 10 year survival. Hypotheses were explored with standardized rate ratios (RR) and tested with logistic regression models.

RESULTS

Significant inverse associations of poverty (RR = 0.79) and inadequate health insurance (RR = 0.80) with survival were observed in the California, while they were non-significant or non-existent in Ontario. The direct associations of primary care physician (RRs of 1.32 versus 1.11) and gastroenterologist (RRs of 1.56 versus 1.15) supplies with survival were both stronger in Ontario than California. The supply of primary care physicians took precedence. Probably mediated through the initial course of treatment, it largely explained the Canadian advantage.

CONCLUSIONS

Poverty and health insurance were more predictive in the USA, community physician supplies more so in Canada. Canada's primary care protections were greatest among the most socioeconomically vulnerable. The protective effects of Canadian health care prior to enactment of the Affordable Care Act (ACA) clearly suggested the following. Notwithstanding the importance of insuring all, strengthening America's system of primary care will probably be the best way to ensure that the ACA's full benefits are realized. Finally, Canada's strong primary care system ought to be maintained.

Screening rates for colorectal cancer in Canada: a cross-sectional study

INTRODUCTION

Implementation of population-based colorectal cancer (CRC) screening programs should reduce disparities in participation in CRC screening. We estimated CRC screening rates in 2012 in Canada and assessed predictors of screening in provinces with and without well-established population-based screening programs.

METHODS

We used data from the Canadian Community Health Survey for 2012 to calculate the prevalence of up-to-date CRC screening, defined as fecal occult blood testing (FOBT) within 2 years before the survey or flexible sigmoidoscopy or colonoscopy within 10 years before the survey, or both. Weighted proportions of individuals with up-to-date screening were calculated and logistic regression analysis performed to assess predictors of up-to-date CRC screening, including differences in participation by income level.

RESULTS

The prevalence of up-to-date CRC screening among people 50-74 years of age in 2012 was 55.2%, ranging from 41.3% in the territories to 67.2% in the province of Manitoba. The rate for sigmoidoscopy or colonoscopy was 37.2% (highest in Ontario, at 43.3%), and for FOBT it was 30.1% (highest in Manitoba, at 51.7%). About 41% of those who had an FOBT also had a sigmoidoscopy or colonoscopy. Individuals in the highest income group were more likely than those in lower-income groups to be up to date with CRC screening, even in provinces with well-established population-based screening programs.

INTERPRETATION

More than half of Canadians were up to date with CRC screening in 2012, but there were large differences among provinces. Differences by income group in provinces with population-based screening programs need particular attention.