Nasopharyngeal and hypopharyngeal carcinoma risk among immigrants in Sweden

Abstract

Environmental exposures, particularly infection with Epstein‐Barr virus (EBV) and tobacco, are known risk factors for oral cancer. Studies in migrants may provide valuable insight into the environmental and genetic etiology of cancer. We wanted to define nasopharyngeal and hypopharyngeal carcinoma among immigrants in Sweden. The nationwide Swedish Family‐Cancer Database (FCD) was used to calculate standardized incidence ratios (SIRs) for nasopharyngeal and hypopharyngeal carcinomas among the first‐generation immigrants compared to the native Swedes. The FCD included 1969 and 691 cases of nasopharyngeal and hypopharyngeal carcinoma in the male and female Swedes and 178 and 65 cases in immigrants, respectively. The median age at diagnosis (years) was 63 among Swedes and 55 among immigrants. The risk of nasopharyngeal carcinoma was significantly higher in male (SIR = 35.6) and female (24.6) Southeast Asians, male (12.4) and female (34.7) North Africans, male (4.9) and female (10.9) Asian Arabs and some other male Asians immigrants (6.2 to 6.7). Among immigrants from European countries, only the men from former Yugoslavian showed an elevated risk (2.7). Hypopharyngeal carcinoma risk was only increased among the male immigrants from the Indian Subcontinent (5.4). Early life infection with EBV in countries of origin and probably a minor contribution by tobacco smoking may be the main environmental exposures influencing nasopharyngeal carcinoma risks among immigrants to Sweden. The high rates of hypopharyngeal carcinoma among Indian immigrants may point to a continued using of smokeless tobacco.

Age‐ and time‐dependent changes in cancer incidence among immigrants to Sweden: colorectal, lung, breast and prostate cancers

“…However, no direct data is available to show the trend of smoking prevalence among immigrants. 19,20,27 An increasing incidence of breast cancer in many non-European countries from where people migrated to Sweden was reported. 28 Simultaneously, our previous experience showed that the overall breast cancer incidence was increased in immigrants, in parallel with the length of stay in Sweden, whereas the effect of age at immigration was not explored.…”

“…19,20 Age-specific incidence rates estimated among native Swedes within the FCD were selected as reference for which was served to calculate expected number of cases. To catch the maximum number of cases during five decades of residence in Sweden, immigrants were also classified according to country of origin-and sex-specific colorectal, lung, breast and prostate cancers risk based on the results presented in Table 1 (high-risk: SIR significantly increased; low-risk: SIR significantly decreased and other: nonsignificant SIR).…”

Morbidity and mortality in gynecological cancers among first‐ and second‐generation immigrants in Sweden

“…Like our previous studies, [25][26][27] we calculated standardized incidence ratios (SIRs) and standardized mortality ratios (SMRs) as the ratio of observed to expected number of cases and deaths. The expected number of cases and deaths were calculated in 5-year age groups and in 10-year intervals for the years between 1958 and 2008.…”

Declining Incidence of Nasopharyngeal Carcinoma in Brunei Darussalam: a Three Decade Study (1986-2014)

“…Environmental factors are important as migrant studies have shown that the rates decline to intermediate rates between the countries of origin and countries of residence. (Yu and Hussain 2009;Mousavi et al, 2010). Low economic social status, an indirect indicator to exposures of the risk factors has also been reported to be associated with NPC.…”