A record of all known cases of nasopharyngeal carcinoma in Malaysia
is complete for 10 years from 1968 to 1977. Special efforts in case-finding were made
in the State of Selangor where conditions are optimal. Age-adjusted incidence rates
among Chinese males and females were 16-5 and 7-2 per 100,000, among Malay males
and females 2*3 and 0-7 and among Indian males, 1.0. There were no significant
changes in incidence rates over the 10-year period for sex and ethnic groups, or for
Chinese subethnic groups. In Chinese subethnic groups, rates were highest among
Cantonese, moderate among Khek and lowest among Hokkien and Teochiu.
Standardized incidence ratios using Selangor as the standard population indicate
considerable under-reporting in the less urban states of Malaysia, particularly among
females. In Selangor, incidence rates were similar for urban and rural residents, but
the frequency of cases was higher among Chinese working in industry and living in
poor neighbourhoods.