Nasopharyngeal cancer in Greenland. The incidence in an Arctic Eskimo population.

Nasopharyngeal cancer is very common among the Chinese in various parts of the world, particularly Southern China, and frequent in certain other Mongoloid groups in Southeast Asia. Also, the incidence among the Eskimos of the western Canadian Arctic and Alaska is considerably higher than would be expected. Ths paper reports for the first time the incidence of nasopharyngeal cancer among native Greenlanders, an Eskimo population with some admixture of Caucasian blood. During 1955-1976, thirty-five cases of nasopharyngeal cancer were diagnosed. Ninety-four per cent (33 cases) were squamous cell carcinomas, including lymphoepitheliomas. Incidence rates 1965-1976, age adjusted to the "world" population distribution, were 12.3 and 8.5 per 100,000 per annum for males and females respectively. These rates are among the highest recorded in the world and significantly higher than among the Caucasian population in Denmark. Compared with other high risk populations nasopharyngeal cancer among Greenlanders had an older age distribution and a lower male-to-female sex ratio. An additional 11 cases with malignant involvement, seeminly confined only to cervical lymph nodes, may have included some undiagnosed nasopharyngeal cancers. Thus the calculated incidence rates of this study could represent only minimum rates. Further research is needed especially with regard to the HL-A profile and to possible traces of Epstein-Barr virus infection.