Mammography rates for breast cancer screening: a comparison of First Nations women and all other women living in Manitoba, Canada, 1999-2008.

INTRODUCTION: First Nations (FN) women historically have low rates of preventive care, including breast cancer screening. We describe the frequency of breast cancer screening among FN women living in Manitoba and all other Manitoba (AOM) women after the introduction of a provincial, organized breast screening program and explore how age, area of residence, and time period influenced breast cancer screening participation. METHODS: The federal Indian Registry was linked to 2 population-based, provincial data sources. A negative binomial model was used to compare breast cancer screening for FN women with screening for AOM women. RESULTS: From 1999 through 2008, 37% of FN and 59% of AOM women had a mammogram in the previous 2 years. Regardless of area of residence, FN women were less likely to have had a mammogram than AOM women (relative rate [RR] = 0.69 in the north, RR = 0.55 in the rural south, and RR = 0.53 in urban areas). CONCLUSIONS: FN women living in Manitoba had lower mammography rates than AOM women. To ensure equity for all Manitoba women, strategies that encourage FN women to participate in breast cancer screening should be promoted.

Geographical disparities of rectal cancer local recurrence and outcomes: a population-based analysis.

BACKGROUND: Challenges exist in providing high-quality cancer treatments to populations spread over large geographical areas. Local recurrence of rectal cancer is a complicated clinical problem associated with high morbidity and mortality. OBJECTIVES: objectives of this study were to evaluate population-based rates and predictors of local recurrence of rectal cancer in the Province of Manitoba, Canada, with emphasis on the effects of geography. DESIGN: : This was a population-based retrospective analysis. Administrative data from the Manitoba Cancer Registry and individual patient charts were reviewed. SETTINGS: Patients with stages I to III rectal cancer who underwent surgery with curative intent in Manitoba between 2004 and 2006 were included. MAIN OUTCOME MEASURES: The primary outcome was the development of local recurrence after surgical resection. RESULTS: Three hundred seventy patients with a mean age of 67 years were identified. The 5-year local recurrence rate was 17.4%. In multivariate analysis, relative to Winnipeg residents, rural residents, regardless of where they underwent surgery, had an increased risk of local recurrence (HR, 3.47; 95% CI, 1.74-6.92 for surgery in Winnipeg; HR, 2.98; 95% CI, 1.59-5.57 for surgery in rural Manitoba). The absence of both neoadjuvant radiotherapy and adjuvant chemotherapy was associated with a higher risk of local recurrence. Higher risk of mortality was noted for rural patients (HR, 1.90; 95% CI, 1.24-2.89) and for those who developed local recurrence (HR, 2.01; 95% CI, 1.27-3.19). CONCLUSION: Local recurrence rates for rectal cancer are high in Manitoba. Geography is an important variable, because rural status is associated with higher local recurrence rates and decreased survival. The use of neoadjuvant radiotherapy was an important predictor of lower local recurrence rates. Further initiatives are imperative to identify why rural patients experience differences in outcomes in Manitoba.

Longer waiting times for patients undergoing colorectal cancer surgery are not associated with decreased survival.

BACKGROUND AND OBJECTIVES: Wait times are a growing concern in Canada's publicly-funded healthcare system. We sought to determine if increased wait times for colorectal cancer (CRC) treatments resulted in worse outcomes. METHODS: A population-based retrospective cohort analysis of wait times for CRC patients undergoing major surgical resections in Manitoba, Canada, between 2004 and 2006 was undertaken. Administrative records were utilized to estimate total wait time (TWT), defined as the sum of time from index contact with the healthcare system to diagnosis of CRC (diagnostic wait time [DWT]) and the time from diagnosis to first cancer treatment (treatment wait time [TxWT]). Multivariate Cox regression analysis of 5-year overall survival was performed to determine the effect of TWT quartiles on survival. RESULTS: One thousand six hundred twenty eight patients with stage I-IV CRC underwent major surgery with a median TWT of 95 days. Predictors of lower 5-year survival included advanced age, higher stage, lower economic status, increased medical comorbidity, urgent presentation, living between 101 and 500 km from the Provincial cancer center, and not receiving adjuvant chemotherapy. After controlling for these variables, TWT quartiles were not associated with survival (P = 0.4898). CONCLUSIONS: On a population basis, increased TWT was not associated with worse survival, while controlling for important confounders.

Does geography influence the treatment and outcomes of colorectal cancer? A population-based analysis.

BACKGROUND: The Canadian province of Manitoba covers a large geographical area but only has one major urban center, Winnipeg. We sought to determine if regional differences existed in the quality of colorectal cancer care in a publicly funded health care system. METHODS: This was a population-based historical cohort analysis of the treatment and outcomes of Manitobans diagnosed with colorectal cancer between 2004 and 2006. Administrative databases were utilized to assess quality of care using published quality indicators. RESULTS: A total of 2,086 patients were diagnosed with stage I to IV colorectal cancer and 42.2% lived outside of Winnipeg. Patients from North Manitoba had a lower odds of undergoing major surgery after controlling for other confounders (odds ratio (OR): 0.48, 95% confidence interval (CI): 0.26 to 0.90). No geographic differences existed in the quality measures of 30-day operative mortality, consultations with oncologists, surveillance colonoscopy, and 5-year survival. However, there was a trend towards lower survival in North Manitoba. CONCLUSION: We found minimal differences by geography. However, overall compliance with quality measures is low and there are concerning trends in North Manitoba. This study is one of the few to evaluate population-based benchmarks for colorectal cancer therapy in Canada.

Trends in time to diagnosis of colon cancer and impact on clinical outcomes.

BACKGROUND: There has been a rapid increase in screening for colorectal cancer (CRC) over the past several years in North America. This could paradoxically lead to worsening outcomes if the system is not adapted to deal with the increased demand. For example, this could create increased wait times for endoscopy and delayed time to CRC diagnosis, which could worsen clinical outcomes such as stage at diagnosis and/or survival. No previous Canadian study has evaluated the association between time to CRC diagnosis and clinical outcomes. METHODS: The present historical cohort study used Manitoba's population-based cancer registry and Manitoba Health administrative databases. The effect of time to diagnosis on patient survival was evaluated using Cox regression analysis with adjustment for stage at diagnosis, grade of CRC, age, sex, socioeconomic status, comorbidity index score and year of CRC diagnosis. The association between time to diagnosis and CRC stage at diagnosis was evaluated using multivariate logistic regression analysis. RESULTS: The median time to CRC diagnosis increased significantly from 72 days (95% CI 61 days to 83 days) in 2004 to 105 days (95% CI 64 days to 129 days) in the first three months of 2009 (P=0.04). There was no significant association between time to diagnosis and survival. Individuals with the longest time to diagnosis were less likely to have stage III/IV CRC at diagnosis (quartile 4 versus quartile 1: OR 0.50 [95% CI 0.33 to 0.75). CONCLUSION: Time to CRC diagnosis is continuing to increase in Manitoba. Although the present study did not detect a significant negative clinical effect of increasing time to diagnosis, additional studies are required.

A lack of association between increases in gastrointestinal, liver, and urologic cancers and cyanobacterial contamination of fresh water lakes in Manitoba.

Cyanobacteria or blue-green algae are becoming increasingly abundant in North American fresh water lakes. Toxins produced by cyanobacteria have been associated with gastrointestinal injury, liver failure, and nephrotoxicity. They have also been implicated in the pathogenesis of gastrointestinal and liver cancers. The purpose of the present study was to determine whether the incidence rates of gastrointestinal, liver, and urologic cancers are increasing in the province of Manitoba and, if so, whether these increases spatially and/or temporally correlate with areas where cyanobacterial contamination of fresh water lakes have been identified. Cancer incidence data were obtained from the Manitoba Cancer Registry. Cyanobacterial contamination data, as reflected by microcystin toxin concentrations, were available from the Manitoba Water Stewardship. ArcGIS mapping was employed to document spatial and temporal relationships between cancer incidence and cyanobacterial data. The results revealed that although the incidence rates for all three cancers have increased over the past 20-25 years, these increases were not disproportionally higher in zones with high microcystin toxin determinations. The results of this study argue against increased exposure to cyanotoxins as an explanation for the increase in gastrointestinal, liver and urologic cancers in Manitoba.

Population-based analysis of breast cancer treatment by intrinsic sub-type in Manitoba, Canada.

BACKGROUND: Few descriptive epidemiological studies on the incidence, treatment and survival can accurately reflect a whole population. Manitoba, Canada has an accurate cancer registry, a drug information program network and a breast screening program since 1995. This combined with a stable population provides true population data that can accurately describe the region. METHODS: Using a retrospective cohort design all Breast Cancer cases were obtained from 2004-2010 (N=5399) and grouped by Intrinsic sub-type. Identifiable co-morbidities, prescribed endocrine therapy, staging, surgery, treatment and overall and disease-free survival by intrinsic sub-type were evaluated. RESULTS: Prevalence of Luminal A (41.7%), Luminal B HER2- (15.6%), Luminal B HER2+ (8.9%), Basal-like(10.8%), and HER2+ non-luminal (5.1%) were consistent with other descriptive studies in Canada and Spain. Over this time period the number of lumpectomies increased 1.7% per year (P=0.007). There was a steady increase of 3.4% per year in the use of aromatase inhibitors (P=0.005). Pre-menopausal patients had an increased proportion of HER2+ and Basal-like sub-types. The 7year overall/disease-free survival percentages for Luminal A, Luminal B HER2-, Luminal B HER2+, Basal-like, and HER2+ non-luminal were 88.7%/83.6, 78.2%/73.0, 81.5%/73.3%, 67.7%/63.2%, 70.4%/65.6% respectively. CONCLUSIONS: Reasons for variability in the prevalence of intrinsic sub-type by region is not fully understood. Manitoba is unique due the stability of the population, completeness of the registry and length of breast cancer screening program. Few true population-based studies grouped by intrinsic sub-type are available. IMPACT: Descriptive epidemiological studies guide future research by identifying factors that can affect treatment, recurrence, and survival.

Colorectal cancer screening in first nations people living in Manitoba.

BACKGROUND: Because the burden of colorectal cancer (CRC) seems to be increasing in First Nations, it is important to better understand CRC screening utilization. The objective of this study was to describe CRC screening among First Nations living in Manitoba. METHODS: The Federal Indian Register was linked to two provincial databases. A negative binomial model was used to compare the probability of First Nations having a fecal occult blood test (FOBT), colonoscopy, or flexible sigmoidoscopy (FS) with all other Manitobans. RESULTS: First Nations who lived in Winnipeg were significantly less likely to have had a FOBT in the previous 2 years than all other Manitobans who lived in Winnipeg [rate ratio (RR) = 0.40; 95% confidence intervals (CI), 0.37-0.44]. There was no difference in the likelihood of having a colonoscopy or FS for First Nations individuals who resided in northern Manitoba compared with all other Manitobans (RR, 1.04; 95% CI, 0.91-1.19). However, First Nations who lived in the rural south or urban areas were less likely than all other Manitobans to have had a colonoscopy or FS (RR, 0.81, 95% CI, 0.75-0.87, rural south; RR, 0.86, 95% CI, 0.81-0.92, urban). CONCLUSIONS: First Nations living in Winnipeg were significantly less likely to be screened for CRC using the FOBT. Colonoscopy and FS use depended on area of residence. IMPACT: First Nations experience barriers that impede the use of CRC screening. Further research is needed to understand these barriers to extend the benefit of CRC screening to this population. Cancer Epidemiol Biomarkers Prev; 24(1); 241-8. ©2014 AACR.

Concordance with ASCO guidelines for surveillance after colorectal cancer treatment: a population-based analysis.

PURPOSE: Intensive surveillance after curative treatment of colorectal cancer (CRC) is associated with improved overall survival. This study examined concordance with the 2005 ASCO surveillance guidelines at the population level. METHODS: A cohort of 250 patients diagnosed with stage II or III CRC in 2004 and alive 42 months after diagnosis was identified from health administrative data in Manitoba, Canada. Colonoscopy, liver imaging, and carcinoembryonic antigen (CEA) testing were assessed over 3 years. Guidelines were met if patients had at least one colonoscopy in 3 years and at least one liver imaging test and three CEA tests annually. Multivariate logistic regression assessed the effect of patient and physician characteristics and disease and treatment factors on guideline concordance. RESULTS: Guidelines for colonoscopy, liver imaging, and CEA were met by 80.4%, 47.2%, and 22% of patients, respectively. Guideline concordance for colonoscopy was predicted by annual contact with a surgeon, higher income, and the diagnosis of colon (rather than rectal) cancer. Adherence was lower in those older than 70 years and with higher comorbidity. For liver imaging, significant predictors were annual contact with an oncologist, receipt of chemotherapy, and diagnosis of colon cancer. Concordance with CEA guidelines was higher with annual contact with an oncologist and high levels of family physician contact, and lower in urban residents, in those older than 70, and in those with stage II disease. CONCLUSION: Completion of recommended liver imaging and CEA testing fall well below guidelines in Manitoba, whereas colonoscopy is better provided. Addressing this gap should improve outcomes for CRC survivors.