Nasopharyngeal cancer incidence varies among Asian American subgroups
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Incidence of nasopharyngeal cancer differed greatly among Asian American ethnic subgroups, with significantly higher risk among Chinese and Laotian individuals compared with white individuals, according to study results.
The findings, presented during the American Association for Cancer Research Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved, highlight the need to move away from studying Asian Americans as a single racial group in terms of cancer risk, according to Alice W. Lee, PhD, MPH, cancer epidemiologist and assistant professor in the department of health science at California State University, Fullerton.
“What is striking about nasopharyngeal cancer is the racial disparities involved,” Lee said during the presentation. “Incidence is about three-to-four-times higher among the Asian/Pacific Islander population compared with all other races. Yet, few studies have examined incidence by Asian American ethnic subgroup, which is worth examining given that Asian Americans constitute a heterogenous racial group and ethnic-specific differences are often missed when studied in aggregate.”
Nasopharyngeal cancer is relatively rare in the U.S, with less than one case per 100,000 people, Lee said.
Lee and colleagues pooled data from 13 population-based cancer registries included in the SEER database to examine incidence of nasopharyngeal cancer among Asian American ethnic subgroups compared with white Americans.
The study included approximately 9,700 cases of nasopharyngeal cancer diagnosed between 1990 and 2014. Researchers divided the cohort into nine ethnic subgroups: Chinese, Japanese, Filipino, Korean, Asian Indian/Pakistani, Vietnamese, Laotian, Cambodian and Native Hawaiian/Pacific Islander.
Results showed incidence of nasopharyngeal cancer was 14.71 (95% CI, 11.87-18.02) times higher among Laotian Americans and 10.73 (95% CI, 10.19-11.29) times higher among Chinese Americans compared with white Americans.
“Our results also showed notably higher incidence among Vietnamese and Cambodians, whereas little to no difference in incidence was observed for the Asian Indian/Pakistani and Japanese subgroups,” Lee said.
Researchers further examined whether differences in incidence persisted across different histology types and found a particularly increased risk for differentiated and undifferentiated nonkeratinizing tumor subtypes. Compared with whites, Laotians had a more than 30-fold higher incidence (incidence rate ratio [IRR] = 30.19; 95% CI, 17.97-47.45) of differentiated nonkeratinizing tumors, and researchers observed a nearly 25-fold higher incidence of undifferentiated non-keratinizing tumors among Chinese (IRR = 24.82; 95% CI, 21.97-28.02) and Laotian Americans (IRR = 24.95; 95% CI, 15.24-38.91).
“Based on our analysis, we conclude that the risk for developing nasopharyngeal cancer varies substantially across ethnic subgroups among Asian Americans,” Lee said. “When studies highlight the higher incidence of nasopharyngeal cancer among Asian Americans, they overlook the ethnic-specific disparities that exist, particularly for Laotians and Chinese. This is important, as these differences can help inform disease etiology, as well as improve prevention efforts. It will be interesting for future research to explore the environmental, behavioral and genetic factors that may account for these findings.”
Two factors known to increase risk for nasopharyngeal cancer include Epstein-Barr virus and diet — particularly consumption of salt-preserved foods, which is known to be high among the Asian population, Lee added.
“More research is needed to better understand the ethnic-specific risk profiles,” she said. “Regardless, our study highlights the importance of disaggregating the Asian American population data to ensure critical disparities by ethnic subgroup are not missed.”
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Lee AW. Abstract PO198. Presented at: American Association for Cancer Research Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved (virtual conference); Oct. 6-8, 2021.
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