Distribution and Clustering of Cutaneous T-Cell Lymphoma (CTCL) Cases in Canada During 1992 to 2010

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Background Several risk factors have been implicated in acute myeloid leukemia (AML) leukemogenesis. However, the epidemiologic distribution and precise triggers for AML in Canada remain poorly understood. Methods In this study, demographic data for AML patients in Canada from 1992 to 2010 were analyzed using 3 independent population‐based cancer registries. The AML incidence and mortality rates were examined at the levels of province/territory, city, and forward sortation area (FSA) postal code. Results In total, 18,085 patients were identified. AML incidence was documented to be 30.61 cases per million individuals per year (95% confidence interval [CI], 30.17‐31.06) from 1992 to 2010. Five industrial cities in Ontario were identified where incidence rates were significantly higher than the national average: Sarnia, Sault Ste. Marie, Thunder Bay, St. Catharines, and Hamilton. Analysis at the FSA postal code level identified significant patient clusters of AML in these cities. Specifically, FSA N7V in Sarnia, Ontario had an incidence of 106.81 (95% CI, 70.96‐161.86) cases per million individuals per year, which is >3 times higher than the national average. The pollution from local oil refineries and chemical plants in Sarnia may be implicated as a risk factor for AML in that city. Analysis of mortality rates at the province and city levels corroborated the findings from the incidence data. Conclusion These results provide a comprehensive analysis of AML burden in Canada and reveal striking geographic case clustering in industrial Ontario cities and potentially implicate exposure to materials/pollution from these plants as an important risk factor for developing AML in Canada.

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Analysis of acute myeloid leukemia incidence and geographic distribution in Canada from 1992 to 2010 reveals disease clusters in Sarnia and other industrial US border cities in Ontario

Ghazawi

Cyr

et al. 2019

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“…Clues pointing to attribution of environmental exposure include the concomitant rise in CTCL cases with industrial expansion, increased incidence in nonblood‐related relatives, and known associations of occupational chemicals with other hematologic malignancies . Clustering has been identified in several studies across the globe, including Sweden, Canada, Pittsburgh, Pennsylvania, and Texas . The analysis in Texas found 3 communities in metropolitan Houston with rates of CTCL that were between 5 and 20 times higher than the expected population rate .…”

Section: Introductionmentioning

confidence: 99%

Clustering of cutaneous T‐cell lymphoma is associated with increased levels of the environmental toxins benzene and trichloroethylene in the state of Georgia

Clough

Bayakly

Ward

et al. 2020

Background Cutaneous T‐cell lymphoma (CTCL) is a rare form of non‐Hodgkin lymphoma arising in the skin. Geographic clustering of CTCL has recently been reported, but its association with environmental factors is unknown. Benzene and trichloroethylene (TCE) are environmental toxins with carcinogenic properties. The authors investigated associations between geographic clustering of CTCL incidence in the state of Georgia with benzene and TCE exposure. Methods The statewide county‐level incidence of CTCL within Georgia was obtained from the Georgia Cancer Registry for the years 1999 to 2015. Standardized incidence ratios (SIRs) were calculated by dividing observed cases by expected cases using national incidence rates by age, sex, and race. Clustering of CTCL was analyzed using spatial analyses. County‐level concentrations of benzene and TCE between 1996 and 2014 were collected from the Environmental Protection Agency's National Air Toxics Assessment database. Linear regression analyses on CTCL incidence were performed comparing SIRs with levels of benzene and TCE by county. Results There was significant geographic clustering of CTCL in Georgia, particularly around Atlanta, which was correlated with an increased concentration of benzene and TCE exposure. Among the 4 most populous counties in Georgia, CTCL incidence was between 1.2 and 1.9 times higher than the state average, and benzene and TCE levels were between 2.9 and 8.8 times higher. Conclusions The current results demonstrate nonrandom geographic clustering of CTCL incidence in Georgia. To the authors' knowledge, this is the first analysis to identify a correlation between geographic clustering of CTCL and environmental toxic exposures.

“…In this study, we extensively analyzed the epidemiology of PV patients in Canada and found a significant clustering of PV cases in specific Canadian communities. Such epidemiological analyses may shed light on potential risk factors as possible triggers/promoters of this malignancy …”

Section: Introductionmentioning

confidence: 99%

Identification of significant geographic clustering of polycythemia vera cases in Montreal, Canada

Ghazawi

Rahme

et al. 2019

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Background Polycythemia vera (PV) is a chronic myeloproliferative neoplasm associated at times with debilitating symptoms and a significant mortality rate. Understanding the demographics, epidemiology, and geography of this disease may provide further insight into important risk factors associated with its development. The objective of this study was to analyze patient demographics, incidence, and mortality rates, as well as the geographic distribution of PV patients in Canada between 1992 and 2010. Methods This study was achieved by analyzing the Canadian Cancer Registry, Le Registre Québécois du Cancer, and the Canadian Vital Statistics patient databases. Results A total of 4645 patients were diagnosed with PV between 1992 and 2010. While the annual incidence rate of this cancer fluctuated in Canada, mortality rate analysis indicated a decreasing trend. Geographically, PV incidence rates were notably elevated in the province of Quebec compared with the Canadian average. Further analysis of high‐incidence forward sortation areas indicated a striking clustering of cases in the H4W region encompassing the Côte‐Saint‐Luc borough of Montreal, with an incidence of 102.97 (95% confidence interval, 75.11‐137.79) cases per million per year, which is >13 times the national average. Conclusion The residential area of Côte‐Saint‐Luc is an important PV cluster in Canada, with high concentration of retirement homes and geriatric hospices. Also, Jewish residents comprise >60% of the population in this neighborhood. These findings suggest that an older age and, potentially, an inherent genetic predisposition may be implicated in the pathogenesis of this malignancy. This study provides a comprehensive overview of PV burden/geographic distribution of cases in Canada.