Retrospective Study on Nasopharyngeal Carcinoma2

Abstract

In the population of 2 defined areas, Northern and Southern Taiwan, 442 patients with nasopharyngeal carcinoma (NPC) were identified and 343 of them were interviewed during a 1½-year period. Similar interviews were conducted with 1017 persons without the disease, who lived in the neighborhoods of the patients, to serve as controls. The average annual incidence rate was 4.2/100,000 population: 5.8 for males, 2.4 for females, 4.5 for Northern Taiwan, 3.8 for Southern Taiwan, 3.2 for the Taiwanese, and 9.9 for the Mainlander. Age-specific incidence rates rapidly increased in the 30–34 age group, continued to increase gradually until they reached a peak in the 55–59 age group, and declined in the older age groups. Risk of NPC was measured with summary relative risks and chi-square tests. Smoking was. significantly associated with NPC risk. The relative risk indicated that persons smoking more than 20 cigarettes a day had over 2 times the NPC risk of those who never smoked. Working under poorly ventilated conditions also was found associated with NPC risk—over twice as great as in those without this experience. Some nasal symptoms and use of herb drugs and nasal balms or oils were also associated with NPC risk. The etiology of NPC is dicussed in relation to our findings.