Association of Immigration Status and Chinese and South Asian Ethnicity With Incidence of Head and Neck Cancer | Cancer Screening, Prevention, Control | JAMA Otolaryngology–Head & Neck Surgery | JAMA Network
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Figure 1.  Study Flowchart
Study Flowchart

OHIP indicates Ontario Health Insurance Plan.

Figure 2.  Probability of Cancer Diagnosis in the Matched Immigration Cohort
Probability of Cancer Diagnosis in the Matched Immigration Cohort

Cumulative incidence functions comparing risk of cancer diagnosis over time, by subsite, among immigrants (navy line) vs long-standing residents (light blue line).

Figure 3.  Probability of Cancer Diagnosis in the Matched Ethnicity Cohort
Probability of Cancer Diagnosis in the Matched Ethnicity Cohort

Cumulative incidence functions comparing risk of cancer diagnosis over time, by subsite, among immigrants (navy line) vs long-standing residents (light blue line) for Chinese (A, B, E, F) and South Asian (C, D, G, H) individuals.

Table 1.  Baseline Characteristics of Matched Ethnicity Cohort
Baseline Characteristics of Matched Ethnicity Cohort
Table 2.  Age/Sex-Standardized Incidence of Head and Neck Cancer With Adjusted Hazard Ratios Relative to the General Population for Matched Ethnicity Cohort
Age/Sex-Standardized Incidence of Head and Neck Cancer With Adjusted Hazard Ratios Relative to the General Population for Matched Ethnicity Cohort
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    Original Investigation
    From the American Head and Neck Society
    November 5, 2020

    Association of Immigration Status and Chinese and South Asian Ethnicity With Incidence of Head and Neck Cancer

    Author Affiliations
    • 1Department of Otolaryngology–Head and Neck Surgery, University of Toronto, Toronto, Ontario, Canada
    • 2Institute of Health Policy, Management and Evaluation, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
    • 3Institute for Clinical and Evaluative Sciences, Toronto, Ontario, Canada
    • 4Division of Otolaryngology–Head and Neck Surgery, Dalhousie University, Halifax, Nova Scotia, Canada
    • 5Department of Surgical Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
    • 6Department of Medical Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
    JAMA Otolaryngol Head Neck Surg. 2020;146(12):1125-1135. doi:10.1001/jamaoto.2020.4197
    Key Points

    Question  How are immigration status and Chinese and South Asian ethnicity associated with incidence of head and neck cancer (HNC)?

    Findings  This cohort study of 3 328 434 individuals in Ontario, Canada, demonstrated a clear healthy immigrant association, with low rates of HNC observed in immigrant populations. Compared with the general Ontario population, individuals of Chinese and South Asian ethnicity were at greater risk of developing HNC.

    Meaning  This study separates the independent associations of ethnicity and immigration with HNC incidence and identifies certain high-risk ethnocultural groups.

    Abstract

    Importance  Head and neck cancer (HNC) incidence varies worldwide, although it remains one of the most common cancers among those of East Asian and South Asian ethnicity.

    Objective  To determine the association of Chinese and South Asian ethnicity, independent of immigration status, with HNC incidence.

    Design, Setting, and Participants  This was a retrospective population-based matched cohort study that examined data collected between 1994 and 2017 in Ontario, Canada. Data were analyzed between July 2019 and March 2020. Individuals who immigrated to Canada between 1985 and 2017 were classified as immigrants, whereas Canadian-born individuals and those who immigrated prior to 1985 were classified as long-standing residents. Two separate, matched cohorts were created: an immigration cohort, consisting of immigrants and long-standing residents hard matched on age and sex, and an ethnicity cohort, where participants were further matched on ethnicity (Chinese, South Asian, or non-Chinese/non–South Asian).

    Exposures  Chinese ethnicity, South Asian ethnicity, and immigration status.

    Main Outcomes and Measures  Patients newly diagnosed with primary HNC were captured in both the immigration and the ethnicity cohorts. Cause-specific hazard models were used to estimate the association of immigration status and ethnicity with HNC incidence.

    Results  In the immigration cohort, 3 328 434 matched individuals (mean [SD] age, 36.73 [13.46] years; 52.8% female) were followed, across which 3173 unique HNC diagnoses were made. The hazard ratio (HR) for a new diagnosis of oropharynx cancer was lower in immigrants compared with long-standing residents (HR, 0.26 [95% CI, 0.22-0.31]). In the ethnicity cohort, after adjusting for age, sex, rurality, and deprivation, the rate of HNC diagnosis was higher for Chinese individuals (HR, 1.49 [95% CI, 1.36-1.64]) and South Asian individuals (HR, 1.29 [95% CI, 1.14-1.45]), although it was lower for immigrants (HR, 0.48 [95% CI, 0.44-0.52]) when compared with non-Chinese and non–South Asian individuals. There was no difference in the incidence of nasopharynx cancer when comparing immigrants and long-standing residents of Chinese ethnicity.

    Conclusions and Relevance  Immigration status appears to offer a protective effect against a diagnosis of HNC. Chinese and South Asian ethnic groups may experience higher HNC incidence when compared with the general Ontario population.

    Introduction

    Head and neck cancer (HNC) comprises cancers of the oral cavity, larynx, and pharynx,1 and ranks seventh globally in terms of cancer incidence, with striking ethnic and geographic variation.2,3 While oral cancer is not among the 5 most common cancers in many developed nations, it remains the most common cancer among men living in South Asian countries.1,4-8 Similarly, nasopharynx cancer is relatively rare in most parts of the world, although it is endemic within certain regions, including southern China.9,10 Incidence rates of human papillomavirus–associated oropharynx cancer have increased dramatically in several Western countries, relative to other regions.11-13

    The reason for such marked global variation in HNC is not entirely known, although it raises important questions about HNC incidence among certain immigrant and ethnic populations. Traditional risk factors such as tobacco, alcohol, betel quid, and viral exposures have been used to explain much of this worldwide variation, although it has also been suggested that certain racial and ethnic groups may be at intrinsically higher risk of HNC than others.10,14 While several studies have explored HNC incidence by intracountry ethnicity10,14-19 and geographic region,3,10,11 comparative literature assessing the independent effects of ethnicity and immigration status on HNC incidence is lacking.

    In Canada, 22% of the population are first-generation immigrants and approximately half of the visible minority population is of either Chinese or South Asian ethnicity.20 Although immigration might be thought of as a risk factor for HNC, a healthy immigrant effect, where immigrants have improved health outcomes, is often observed.21-25 Presently, it is unknown whether people of South Asian or Chinese ethnicity who recently immigrated to Ontario are at higher risk of HNC than individuals of this same ethnicity who are Canadian born or long-standing residents. Documentation of high-risk cohorts carries important health policy implications as targeted ethnocultural health promotion has proven effective in the prevention of several cancer types, including oral cancer.26-33 To that end, we sought to investigate the independent associations of immigration and Chinese and South Asian ethnicity with HNC risk in Ontario.

    Methods
    Population

    We conducted a population-based, retrospective, matched cohort study using linked administrative data housed at the Institute for Clinical and Evaluative Sciences (ICES). The study population was composed of all adult (≥18 years) immigrants to Ontario, with a landing record between January 1, 1994, and March 31, 2017 (Figure 1). In Ontario, essential medical care is reimbursed by a single, government-operated health insurance system, the Ontario Health Insurance Plan (OHIP). Patients were required to be continuously eligible under OHIP and censored once no longer eligible, allowing for a 180-day grace period to renew eligibility. Ethnicity was identified through a validated algorithm using surnames to identify patients of Chinese ethnicity (sensitivity, 80.2%; specificity, 99.7%) and South Asian ethnicity (sensitivity, 50.4%; specificity, 99.7%).34 All individuals who immigrated to Canada between 1985 and 2017 were classified as recent immigrants, whereas Canadian-born individuals and those who immigrated prior to 1985 where classified as long-standing residents. Only individuals who immigrated after 1994 were included in the present cohort. Individuals who immigrated between 1985 and 1994 were identified to ensure that they were excluded from the long-standing resident cohort.

    This study was conducted and presented in accordance with the Reporting of Studies Conducted Using Observational Routinely Collected Data guidelines.35 The study was approved by the Sunnybrook Health Sciences Centre Institutional Review Board. Patient informed consent was waived because the data used were deidentified.

    Cohort Creation

    To investigate the association of ethnicity and immigration with HNC incidence, 2 entirely separate matched cohorts were created: the matched immigration cohort and the matched ethnicity cohort (Figure 1). To assess the association of immigration status with HNC incidence we defined a matched immigration cohort where, for every immigrant, we identified 1 long-standing resident from the general Ontario population based on a hard match of age (birth year) and sex. The index date for each immigrant was the date of first OHIP eligibility (following their landing date), and controls were assigned a dummy index date corresponding to that of their matched immigrant counterpart.

    To investigate the association of ethnicity with HNC risk, a separate cohort was built: the matched ethnicity cohort. Each immigrant was first classified by ethnicity: Chinese, South Asian, or non-Chinese/non–South Asian. For every immigrant, we then identified 1 long-term resident from the general Ontario population based on a hard match of ethnicity, age (birth year), and sex. Index dates were assigned as stated above.

    Data Sources

    The following data sources were linked and analyzed at ICES. The Immigration, Refugees and Citizenship Canada’s Permanent Resident Database contains immigration applications and landing records for all immigrants since 1985. The Ontario Cancer Registry is a population-based registry that is estimated to capture 96% of incident HNC diagnoses in the province.36,37 The Ontario Marginalization Index quantifies the degree of marginalization across the province with respect to deprivation, residential instability, dependency, and ethnic concentration.38 The Registered Persons Database contains demographic data and date of death for individuals covered under OHIP.39

    Covariates

    Age and sex were obtained from the Registered Persons Database. Rural living status was determined with postal code of residence.40 Comorbidity burden was measured using the Johns Hopkins Adjusted Clinical Groups system score. Total score was calculated and dichotomized with a cutoff of 10 for high comorbidity burden.41,42 Cancer subsite was categorized as either larynx/hypopharynx, nasopharynx, oropharynx, or oral cavity using International Classification of Diseases for Oncology, Third Revision topography codes (eTable 1 in the Supplement). Socioeconomic status was defined based on the material deprivation dimension of Ontario Marginalization Index and reported in quintiles.43 Each covariate was measured at either the index or the dummy date, with the exception of comorbidity burden, which was calculated 1 year after the OHIP eligibility date in order to accommodate the lookback window.

    Outcome

    The outcome of interest was time from index to a new diagnosis of HNC. Second primaries or recurrent cases were excluded. Patients were observed until a diagnosis of HNC, death, or until the end of the study follow-up period (June 30, 2018).

    Statistical Analysis

    The 2 matched cohorts were used to make several comparisons. The immigration cohort was required to examine the association between immigration status and HNC risk, overall, and for each subsite. The ethnicity cohort was used to assess whether the association between immigration status and HNC risk varied by ethnicity. In addition, as all ethnic pairs were balanced with respect to immigration status, the ethnicity cohort was also used to determine the association between ethnicity and cancer risk.

    The distributions of patient demographics and clinical characteristics were reported by immigration and ethnicity status. We performed between-group comparisons using standardized differences to overcome limitations of traditional statistical measures with large sample sizes.44 The standardized difference, or effect size, describes the difference in means in units of standard deviation between 2 groups. Several studies in the medical literature have employed standardized differences for comparing the baseline balance in dichotomous variables between treated and untreated individuals in observational studies.44 We considered a standardized difference of greater than 0.1 (10%) as significant.44 Residual imbalances were further adjusted for in our multivariable models.

    The crude incidence rate of HNC was calculated for immigrant and nonimmigrant populations in the immigration cohort and by ethnicity in the ethnicity cohort, stratified by cancer subsite. Incidence rates for the overall cohort and by cancer subsite were calculated and standardized for age and sex using direct methods and the 1991 Canadian population as the standard.45 This was done to facilitate comparisons with other world regions.

    Cumulative incidence curves illustrating the risk of HNC diagnosis over time were plotted for the overall immigrant and long-standing cohort, by cancer subsite, as well as for the separate ethnicity cohorts. As death was a competing event, both cause-specific and Fine-Gray regression models were implemented to examine the association between immigration, ethnicity, and HNC diagnosis, adjusting for socioeconomic status and rurality.46,47 The Fine-Gray model yielded results similar to those of the cause-specific model. We thus present results from the cause-specific model, as the study poses an etiologic question for which the cause-specific hazard ratios are preferable.47

    Proportionality assumptions were assessed by visual examination of the log-log plots and by including an interaction with time into the model; however, we found no evidence of time-varying effects. An interaction term between ethnicity and immigration was added to test for effect modification. The interaction term was not significant. A robust sandwich variance estimation approach was incorporated to account for the matched design. All analyses were 2-sided, and statistical significance was set at P < .05 or standardized difference of greater than 0.1. Analyses were conducted using SAS Enterprise Guide, version 7.1 (SAS Institute) and R software, version 3.1.2 (R Foundation).

    Results

    The 2 separate match processes for the separate cohorts are outlined in Figure 1. For the immigration cohort, we identified 1 664 217 immigrants (exposure) and 1 664 217 long-standing residents (controls) hard matched on birth year and sex. Demographic characteristics for the total cohort are listed in eTable 2 in the Supplement. On entry into the cohort, immigrants were more likely to live in an urban area, have fewer comorbidities, and have higher deprivation. The median follow-up time was 11.4 years (interquartile range [IQR], 6.1-16.8 years) for the entire cohort, 11.7 years (IQR, 6.2-17.0 years) for immigrants, and 11.1 years (IQR, 6.0-16.6 years) for the long-standing resident controls.

    For the ethnicity cohort (Table 1), we identified 242 726 Chinese immigrants matched to 242 726 long-standing Chinese residents of Canada. Similarly, 149 905 South Asian immigrants were matched to an equal number of long-standing South Asian residents of Canada. A total of 1 210 948 non-Chinese/non–South Asian immigrants were matched to the same number of long-standing residents who were neither Chinese nor South Asian. All groups were hard matched based on ethnicity, age, and sex. After matching, differences were noted in comorbidity burden, rurality, and deprivation scores. The majority of Chinese immigrants were born in East Asia (94.2% in China, Hong Kong, and Taiwan), and the majority of South Asian immigrants were born in South Asia (90.5% in India, Pakistan, and Bangladesh).

    Immigration Cohort Analysis

    After direct age–sex standardization, the rate of HNC diagnosis was 9.06 per 100 000 for immigrants and 18.04 per 100 000 for long-standing residents (Table 2). Cumulative incidence of HNC diagnosis differed significantly for all HNC cancer subsites (Figure 2). In multivariable cause-specific hazard models further adjusting for rurality, deprivation, and comorbidity burden, the risk of a diagnosis of oral cavity, oropharynx, and larynx cancer was lower in immigrant populations. This was most significant for patients with oropharynx cancer (hazard ratio [HR], 0.25; 95% CI, 0.22-0.30), though differences were also noted for oral cavity (HR, 0.53; 95% CI, 0.47-0.61) and larynx cancers (HR, 0.51; 95% CI, 0.42-0.61). In adjusted analysis controlling for age, sex, rurality, deprivation, and comorbidity burden, the overall hazard for HNC diagnosis in cause-specific hazard regression models was 0.48 (95% CI, 0.44-0.52) for immigrants relative to long-standing residents.

    Ethnicity Cohort Analysis

    Cumulative incidence of HNC diagnosis for Chinese and South Asian ethnicity, stratified by immigration status, is presented in Figure 3. In multivariable cause-specific hazard regression models implemented on the matched ethnicity cohort, the overall rate of HNC was higher for Chinese individuals (HR, 1.49; 95% CI, 1.36-1.64) and South Asian individuals (HR, 1.29; 95% CI, 1.14-1.45) compared with non-Chinese/non-South-Asian individuals after adjusting for age, sex, rurality, deprivation, and comorbidity burden (eTable 3 in the Supplement).

    Nasopharynx Cancer

    The incidence of nasopharynx cancer was higher among both long-standing Chinese residents (6.99 per 100 000 person-years) and Chinese immigrants (6.94 per 100 000 person-years) compared with 0.60 and 0.93 per 100 000 person-years for the long-standing resident and immigrant reference populations, respectively (Table 2). There was no significant difference in the cumulative incidence between Chinese long-standing residents and Chinese immigrants (Figure 3).

    Oral Cancer

    Similarly, the incidence of oral cavity cancer was high among both long-standing South Asian residents (7.05 per 100 000 person-years) and South Asian immigrants (6.83 per 100 000 person-years) compared with the reference long-standing resident and immigrant populations (5.31 and 3.23 per 100 000 person-years, respectively). Long-standing Chinese residents had a higher incidence of oral cancer relative to immigrant Chinese (Figure 3). For South Asian matches, no difference was observed between immigrant and nonimmigrant pairs (Figure 3).

    Discussion

    The results of this investigation begin to expose the unique relative associations between immigration and ethnicity on HNC incidence. These results indicate that immigration status in general appears to be protective against a diagnosis of HNC. However, Chinese and South Asian ethnic groups experience higher HNC incidence, relative to the general reference population, irrespective of immigration status.

    Immigration Status

    Although immigration might be thought of as a risk factor for HNC, a healthy immigrant effect, where immigrants have improved health relative to the general population, is well documented.21-25 This may stem from positive selection bias, whereby those with healthier habits are more likely to immigrate than their less healthy counterparts. A temporality to this effect is often observed,22-24,48,49 although in this study a reduced rate of HNC incidence among immigrant populations relative to the general population was observed for up to 25 years from date of landing. Johnson et al50 previously found that immigration status offered a protective effect in a Canadian population (OR, 0.38; 95% CI, 0.20-0.71) and similar findings have been demonstrated in Denmark.51 This work builds on these observations through a population-level analysis in a robust, matched cohort.

    Oropharynx Cancer

    The discrepancy between HNC incidence among immigrant vs long-standing resident populations was most prominent for patients with oropharynx cancer (HR, 0.25; 95% CI, 0.22-0.30). Oropharynx cancer incidence is increasing, a trend that has been observed predominately in economically developed nations, including Canada.1,11,19 Changes in sexual behaviors and increased number of total and oral sexual partners are believed to have led to increased oral human papillomavirus exposure and, consequently, a rise in the incidence of oropharynx cancer.12,13,52-55 These changes in sexual behaviors occur predominantly in more developed countries, which may explain these differences, as the majority of immigration to Canada is from less economically developed nations.20

    Nasopharynx Cancer

    The nasopharynx was the only subsite in which the immigrant population did not have lower cancer incidence relative to the general population. This is unsurprising, given the large number of individuals who immigrate to Canada from endemic areas. The reported incidence rates among both long-standing and immigrant Chinese populations (6.99 and 6.94 per 100 000 person-years, respectively) were significantly elevated compared with China’s overall incidence rate (2.8 per 100 000 person-years in men and 1.9 per 100 000 person-years in women), recognizing that a 50-fold intracountry variation exists within China.10,18 The population of southern China, including Hong Kong, has a dramatically elevated rate of nasopharynx cancer, and this region has figured prominently in immigration to Canada.56

    To date, most migrant studies looking at nasopharynx cancer have demonstrated that individuals who immigrate from high-risk to low-risk regions retained incidence rates intermediate to natives of their host region of origin.57,58 Buell57 was among the first to document this in 1972 by showing a gradient of lower nasopharynx cancer risk for second-generation and third-generation Californians of Chinese ethnicity. A systematic review of 16 studies further supports this association.58 Many of these studies, however, are cross-sectional and none employed matching techniques. In the present investigation, we did not observe any difference in nasopharynx cancer incidence between long-standing residents and immigrant populations of Chinese ethnicity, suggesting genetic and ethnic factors as a significant driver of nasopharynx cancer. Our inability to control for known associations, such as family history and genotype, limits our ability to draw definitive conclusions.10,59 Further studies in other countries with data holdings that contain immigration and ethnicity data as well as registries that may be able to further control for these residual confounders are warranted.

    Oral Cancer

    Among immigrants and long-standing residents of South Asia, the rates of oral cancer (6.8 and 7.1 per 100 000 person-years, respectively) were higher than those of the reference population and comparable with the incidence rates reported for India (7.1 per 100 000 person-years) and South Central Asia (7.3 per 100 000 person-years).3,29,60 Previous studies examining the relative incidence of oral cancer in ethnic populations noted higher incidence among South Asian populations living in Britain,15,16,61 although not Australia.17 It is expected that the lifestyles and cultural practices of immigrants, many of which are risk factors for oral cancer,6,14,62-65 converge with those of the general population over time.66 Betel nut use has a strong cultural role that may transcend assimilation. At a population level, however, we would anticipate that, on average, long-standing residents of South Asian ethnicity would be less likely to smoke or consume betel nut. The fact that we observed no difference in the hazard of HNC diagnosis for South Asians when stratified by immigration status corroborates suggestions made by previous literature of a genetic predisposition.14 Molecular changes found to be associated with oral carcinomas in Western countries are infrequent in the South Asia where the mutational burden differs.14,67-69

    Implications

    The majority of factors associated with HNC are linked to either individual behavior, environmental context, or genetic interactions. The striking global variation in HNC risk suggests that some ethnic groups may be at intrinsically higher risk than others, although the relative contribution of the independent effect of ethnicity is unclear. To date, there has been limited research on the separate effects of ethnicity and immigration on HNC incidence, given the lack of availability of these variables in many data sets. Even fewer studies have employed a population-based study design, and thus this work contributes a more accurate estimate of HNC incidence.

    The results of the present investigation carry important policy implications. In non-Asian Ontarians we see that oropharynx cancer is now the predominant cancer type, and symptoms should be investigated with this in mind. Regardless of immigration status, individuals of South Asian and Chinese ethnicity have higher rates of oral cavity and nasopharynx cancer, respectively, potentially affecting pretest probability in patients who present with symptoms. This knowledge has the potential to improve early detection of these cancers. As an example, oral cancer screening in high-risk cancer cohorts in India has been shown to be efficacious and cost effective.26-30 Similarly, plasma Epstein-Barr virus DNA screening represents a very promising approach for detecting early-stage nasopharyngeal carcinoma in high-risk cohorts and has been deployed in Hong Kong and other endemic areas.70 In general, screening for cancer should occur with a reliable test, in a high-risk population in which a precancer state can be identified, focusing on a cancer for which effective treatment is available. In North America, screening programs exist for other disease sites including breast cancer and colorectal cancer, for which incidence rates are high (125.1 and 36.8 per 100 000 person-years, respectively).71 Screening programs for oral cavity and nasopharynx cancer have proven effective in endemic areas with similarly high incidence rates (12.3 cases of oral cavity cancer in certain regions of India and 8 cases of nasopharynx cancer per 100 000 person-years in Hong Kong).29,72 A robust, reliable screening program for oropharynx and nasopharynx cancer in the North American context does not yet exist, although use of one may prove effective in similarly high-risk cohorts, particularly in urban areas and communities where these populations live. This work should inform the study population of such a program, were one to be considered.

    Limitations

    The results of this study must be interpreted in context. First, individuals who immigrated prior to 1985 may have been misclassified as long-standing residents. Given the protective effect of immigration, however, this would serve to dilute the observed healthy immigrant effect. The numbers of cancer cases might be underestimated because of omission of surnames that are shared between Anglo-Asians, surnames changed owing to interracial marriages, and the small number of individuals who could not be matched. Similarly, while the Chinese and South Asian naming algorithms are highly specific (>99%), labeling errors can occur.34 The immigration pattern and socioeconomic integration of immigrants in Canada are different from those in other jurisdictions and thus might not be generalizable to other countries. Although the present study used large samples of matched individuals with a high capture rate for cancer, this type of data does not allow for granular risk factor data collection. Tobacco and alcohol use, betel quid use, and sexual activity are all examples of important variables not routinely collected with administrative data. Therefore, given the nature of the data sets used, we were unable to identify more specific family and cultural issues that may underpin the results and lead to residual confounding. Residual confounding is possible as the models did not account for pathological information such as p16 status in patients with oropharynx cancer. Nonetheless, the vast majority (>85%) of patients with oropharynx cancer are p16 positive in recent years,73 and we did partially adjust for this by matching on birth year.

    Conclusions

    Publicly funded cancer systems need to meet the unique needs and requirements of diverse, multicultural populations. This population-based study separates the independent associations of ethnicity and immigration and highlights that Chinese and South Asian ethnic groups residing in Ontario experience higher HNC incidence when compared with the general population. These data serve as baseline data from which comprehensive cancer control strategies can be tailored for ethnoculturally diverse populations.

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    Article Information

    Accepted for Publication: September 22, 2020.

    Published Online: November 5, 2020. doi:10.1001/jamaoto.2020.4197

    Corresponding Author: Antoine Eskander, MD, ScM, Department of Surgical Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, 2075 Bayview Ave, Room T2 047, Toronto, ON M4N 3M5, Canada (antoine.eskander@mail.utoronto.ca).

    Author Contributions: Dr Eskander and Ms Li had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

    Concept and design: Noel, Sutradhar, Forner, Singh, Coburn, Eskander.

    Acquisition, analysis, or interpretation of data: Noel, Sutradhar, Li, Forner, Hallet, Singh, Coburn, Eskander.

    Drafting of the manuscript: Noel, Sutradhar, Singh, Eskander.

    Critical revision of the manuscript for important intellectual content: Noel, Sutradhar, Li, Forner, Hallet, Singh, Coburn, Eskander.

    Statistical analysis: Noel, Sutradhar, Li, Forner, Singh, Coburn.

    Administrative, technical, or material support: Singh, Eskander.

    Supervision: Sutradhar, Hallet, Singh, Coburn, Eskander.

    Conflict of Interest Disclosures: Dr Noel receives salary support through a Canadian Institutes of Health Research Canada Graduate Scholarship Doctoral Award; an Ontario Ministry of Health Clinician Investigator Program grant; an Ontario Graduate Scholarship; a Levinsky Waratah Hold ’Em For Life Oncology Fellowship; a Chapnik, Freeman, and Friedberg Clinician Scientist Award; and a Raymond Ng Doctoral Award. Dr Coburn is funded through the Sherif and MaryLou Hanna Chair in Surgical Oncology Research. Dr Eskander reported grants from Merck and personal fees from Bristol Myers Squibb. Dr Hallet reported grants and personal fees from Ipsen and personal fees from AAA. No other disclosures were reported.

    Funding/Support: This study was supported by the Institute for Clinical and Evaluative Sciences, which is funded by an annual grant from the Ontario Ministry of Health and Long-Term Care.

    Role of the Funder/Sponsor: The Institute for Clinical and Evaluative Sciences had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

    Disclaimer: The opinions, results, and conclusions reported in this article are those of the authors and are independent from the funding sources. The analyses, conclusions, opinions, and statements reported in this article are those of the authors and do not necessarily reflect those of Cancer Care Ontario and the Canadian Institute for Health Information. No endorsement by the Institute for Clinical and Evaluative Sciences, Ontario Ministry of Health and Long-Term Care, Cancer Care Ontario, or Canadian Institute for Health Information is intended or should be inferred.

    Meeting Presentation: This study was presented at the Canadian Society of Otolaryngology–Head and Neck Surgery Annual Meeting; October 31, 2020; Fredericton, New Brunswick, Canada.

    Additional Contributions: We thank Immigration, Refugees and Citizenship Canada for providing access to the database used in this study. We also thank Service Ontario for the use of the Office of the Registrar General for information on deaths.

    Additional Information: Parts of this material are based on data and information provided by Cancer Care Ontario and the Canadian Institute for Health Information. All information and materials in the article are original.

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