Epidemiology of oral and pharyngeal cancers in Khon Kaen, Thailand: a high incidence in females

Background: This study was aimed to describe incidence, trends, and survival of oral and pharyngeal cancers in Khon Kaen, the province situated in the northeast of Thai-land. Methods: Data on oral and pharyngeal cancer cases diagnosed during 1985 - 2001 were retrieved from the population-based cancer registry of Khon Kaen. The final status of the patients was verified by database linkage and follow-up using postcards. Results: Of 1,038 cases, 62.6% were female and 37.4% were male, with a mean age of 63 years. The age-standardized incidence rate (ASR) in females (6.2 per 100 000; 95%CI 5.7-6.7) was significantly higher than in males (3.9 per 100 000; 95%CI 3.5-4.4). Annual percent changes in ASR were 1.7 in females (p<0.05), but 1.2 in males. Lip and buccal cancers were the most common sites respectively; however, the incidence of tongue cancer was increasing in the last period. Eighty five percent of all cases were diagnosed in advanced stage (stage III and IV). The overall five-year relative survival was 43.1%. We found stage distribution and survival did not change during the study period. Conclusion: The considerably high incidence in female suggests a need for research on specific risk factors. Moreover, attempts should be made to detect oral cancers earlier in order to improve the outcomes of cancer control.