We present a national surveillance report on malignant primary brain and other central nervous system (CNS) tumors diagnosed in the Canadian population in 2009–2013. Patients were identified through the Canadian Cancer Registry, an administrative dataset that includes cancer incidence data from all provinces/territories in Canada. Tumor types were classified by site and histology using the definitions from the Central Brain Tumor Registry of the United States (CBTRUS). Incidence rates (IRs) and 95% confidence intervals (CIs) were calculated per 100000 person-years (py) and age-standardized to the 2011 Canadian population for comparisons within Canada and to the 2000 United States population for comparisons with the US. Overall, 12515 malignant brain and other CNS tumors were diagnosed in the Canadian population in 2009–2013 (IR: 8.71/100000 py; 95% CI: 8.56, 8.86); 7085 were among males (IR: 10.06/100000 py; 95% CI: 9.82, 10.29) and 5430 among females (IR: 7.41/100000 py; 95% CI: 7.22, 7.61). Of these, 12115 were classifiable according to histological subgroups defined by CBTRUS. The most common histology was glioblastoma (IR: 4.06/100000 py; 95% CI: 3.95, 4.16). Among those aged 0–19 years, 1130 malignant brain and CNS tumors were diagnosed in 2009–2013 (IR: 3.36/100000 py; 95% CI: 3.16, 3.56). The most common histology among the pediatric population was embryonal tumor (IR: 0.74/100000 py; 95% CI: 0.65, 0.84). These data represent an initial detailed report on the frequency and distribution of primary malignant brain and other CNS tumors diagnosed in the Canadian population in 2009–2013. The reported distributions of tumor diagnoses by sex and age reflected expected patterns based on the literature from similar populations. A report incorporating data on nonmalignant primary brain tumors is forthcoming.

The noninvasive biomarkers fecal immunochemical testing (FIT) and fecal calprotectin (FCP) are sensitive for prediction of mucosal inflammation in inflammatory bowel disease. However, neither test has yet been shown to independently and accurately predict mucosal healing (MH). We aimed to assess the specificity of noninvasive FIT and FCP for MH prediction. In this prospective cohort study of adult inflammatory bowel disease outpatients presenting for colonoscopy, stool samples for FIT and FCP were collected 48 hours before endoscopy. Using MH defined by Simple Endoscopic Score for Crohn's disease (SES-CD = 0), Rutgeert's score (i0), and the Ulcerative Colitis Endoscopic Index of Severity (UCEIS = 3), receiver operator characteristic curves were plotted, and sensitivity, specificity, positive and negative predictive values, and areas under the curve were calculated. Multivariate logistic regression analysis was used to develop a clinical model for noninvasively predicting MH. Eighty patients (40 Crohn's disease and 40 ulcerative colitis) were enrolled. The specificities of FIT <100 ng/mL and FCP <250 μg/g for MH were 0.57 (95% confidence interval, 0.38–0.74) and 0.77 (0.57–0.89), respectively. Positive predictive values for MH for FIT <100 ng/mL and FCP <250 μg/g were 0.78 (0.64–0.87) and 0.77 (0.58–0.90), respectively. In multivariate modeling, combining FIT, FCP, and clinical symptomatic remission improved specificity for MH to 0.90 (0.72–0.97) with positive predictive values of 0.84 (0.60–0.96). Areas under the curve for FIT was higher for patients with ulcerative colitis (0.88) than for patients with Crohn's disease (0.69, P = 0.05). FIT and FCP have similar performance characteristics for identifying MH. Combined, low FIT, low FCP, and clinical remission are specific for MH.

Indigenous communities across the circumpolar north have elevated H. pylori (Hp) prevalence and stomach cancer incidence. We aimed to describe the Hp-associated disease burden among western Canadian Arctic participants in community-driven projects that address concerns about health risks from Hp infection. During 2008–2013, participants underwent Hp screening by urea breath test and gastroscopy with gastric biopsies. We estimated Hp prevalence and prevalence by Hp status of endoscopic and histopathologic diagnoses. Among 878 participants with Hp status data, Hp prevalence was: 62% overall; 66% in 740 Indigenous participants; 22% in 77 non-Indigenous participants (61 participants did not disclose ethnicity); 45% at 0–14 years old, 69% at 15–34 years old, and 61% at 35–96 years old. Among 309 participants examined endoscopically, visible mucosal lesions were more frequent in the stomach than the duodenum: the gastric to duodenal ratio was 2 for inflammation, 8 for erosions, and 3 for ulcers. Pathological examination in 308 participants with gastric biopsies revealed normal gastric mucosa in 1 of 224 Hp-positive participants and 77% (65/84) of Hp-negative participants with sharp contrasts in the prevalence of abnormalities between Hp-positive and Hp-negative participants, respectively: moderate-severe active gastritis in 50 and 0%; moderate-severe chronic gastritis in 91 and 1%; atrophic gastritis in 43 and 0%; intestinal metaplasia in 17 and 5%. The observed pattern of disease is consistent with increased risk of stomach cancer and reflects substantial inequity in the Hp-associated disease burden in western Arctic Canadian hamlets relative to most North American settings. This research adds to evidence that demonstrates the need for interventions aimed at reducing health risks from Hp infection in Indigenous Arctic communities.

The frequency of colorectal cancer (CRC) diagnosis has decreased due to the COVID-19 pandemic. Health system planning is needed to address the backlog of undiagnosed patients. We developed a framework for analyzing barriers to diagnosis and estimating patient volumes under different system relaunch scenarios. This retrospective study included CRC cases from the Alberta Cancer Registry for the pre-pandemic (1 January 2016–4 March 2020) and intra-pandemic (5 March 2020–1 July 2020) periods. The data on all the diagnostic milestones in the year prior to a CRC diagnosis were obtained from administrative health data. The CRC diagnostic pathways were identified, and diagnostic intervals were measured. CRC diagnoses made during hospitalization were used as a proxy for severe disease at presentation. A modified Poisson regression analysis was used to estimate the adjusted relative risk (adjRR) and a 95% confidence interval (CI) for the effect of the pandemic on the risk of hospital-based diagnoses. During the study period, 8254 Albertans were diagnosed with CRC. During the pandemic, diagnosis through asymptomatic screening decreased by 6·5%. The adjRR for hospital-based diagnoses intra-COVID-19 vs. pre-COVID-19 was 1.24 (95% CI: 1.03, 1.49). Colonoscopies were identified as the main bottleneck for CRC diagnoses. To clear the backlog before progression is expected, high-risk subgroups should be targeted to double the colonoscopy yield for CRC diagnosis, along with the need for a 140% increase in monthly colonoscopy volumes for a period of 3 months. Given the substantial health system changes required, it is unlikely that a surge in CRC cases will be diagnosed over the coming months. Administrators in Alberta are using these findings to reduce wait times for CRC diagnoses and monitor progression.

The incidence of BM among Canadian cancer patients is unknown. We aimed to estimate IP of BM at the time of cancer diagnosis and during the lifetime of patients with selected primary cancers. Data on BM at diagnosis from 2010–2017 was obtained from the CCR. Site-specific IPs of BM were estimated from provincial registries containing ≥90% complete data on BM. The CCR IP estimates and the IP estimates from literature were applied to the total diagnosed primary cancers to estimate the number of concurrent BM and lifetime BM from 2010–2017 in Canada, respectively. The annual average number of patients with BM at diagnosis from all cancer sites was approximately 3227. The site-specific IPs of BM at diagnosis were: lung (9.42%; 95% CI: 9.16–9.68%), esophageal (1.58%; 95% CI: 1.15–2.02%), kidney/renal pelvis (1.33%; 95% CI: 1.12–1.54%), skin melanoma (0.73%; 95% CI: 0.61–0.84%), colorectal (0.22%; 95% CI: 0.18–0.26%), and breast (0.21%; 95% CI: 0.17–0.24%). Approximately 76,546 lifetime BM cases (or 5.70% of selected fifteen primary cancers sites) were estimated to have occurred from the 2010–2017 cancer patient cohort. These findings reflect results of population analyses in the US and Denmark. We recommend improved standardization of the collection of BM data within the CCR.

Background: Methylmercury contamination of the environment represents a substantial environmental health concern. Human exposure to methylmercury occurs primarily through consumption of fish and marine mammals. Heavily exposed subgroups include sport or subsistence fishers residing in Arctic communities. We aimed to estimate the association of fish/whale consumption patterns of Canadian Arctic subsistence fishers with the internal dose of methylmercury as measured in hair. Methods: This research was conducted within ongoing community projects led by the CANHelp Working Group in Aklavik and Fort McPherson, Northwest Territories and Old Crow, Yukon. We interviewed each participant using a fish-focused food-frequency questionnaire during September–November 2016 and collected hair samples concurrently. Methylmercury was measured in the full-length of each hair sample using gas chromatography inductively-coupled plasma-mass spectrometry. Multivariable linear regression estimated beta-coefficients and 95% confidence intervals (CIs) for the effect of fish/whale consumption on hair-methylmercury concentrations. Results: Among 101 participants who provided hair samples and diet data, the mean number of fish/whale species eaten was 3.5 (SD:1.9). The mean hair-methylmercury concentration was 0.60 μg/g (SD:0.47). Fish/whale consumption was positively associated with hair-methylmercury concentration, after adjusting for sex, hair length and use of permanent hair treatments. Hair-methylmercury concentrations among participants who consumed the most fish/whale in each season ranged from 0.30–0.50 μg/g higher than those who consumed < 1 meal/week. Conclusions: In this population of Canadian Arctic subsistence fishers, hair-methylmercury concentration increased with fish/whale consumption, but the maximum concentrations were below Health Canada’s 6.0 μg/g threshold for safe exposure.