| Summary: | 碩士 === 國立臺灣大學 === 流行病學與預防醫學研究所 === 99 === Background and Objectives
The incidence of hypopharyngeal cancer and esophageal cancer has been reported to increase in recent two decades in Taiwan. Alcohol intake, betel quid chewing, and smoking were considered to be associated to the increased trends and such lifestyle factors was regarded mostly as cohort effect in age-period cohort model. In recent population-based study in Taiwan, the risk of developing second primary esophageal cancer was showed to be highest in hypophayngeal cancer among oral and pharyngeal cancer. This study aimed to exam the relationship of incidence trends of hypopharyngeal and esophageal cancer, which focused on squamous cell carcinoma and to demonstrate the incidence trends of hypopharyngeal squamous cell carcinoma with second primary esophageal squamous cell carcinoma.
Materials and Methods
A population-based study was conducted using the database from Taiwan Cancer Registry between 1983 and 2007. Patients with hypopharyngeal and esophageal squamous cell carcinoma were identified and gender-specific age-standardized incidence rates of that were calculated. The incidence trends of hypopharyngeal and esophageal squamous cell carcinoma of men were analyzed with autoregressive age-period-cohort model. Age effect, period effect, and cohort effect were obtained respectively. The incidence trends of hypopharyngeal squamous cell carcinoma with ‘synchronous’ second primary esophageal squamous cell carcinoma (difference of diagnostic time between primary and second primary cancer is simultaneous or less than 6 months) and ‘metachronous’ second primary esophageal squamous cell carcinoma (difference of diagnostic time between primary and second primary cancer is more than 6 months) of men were also analyzed.
Results
The result showed the same pattern of age-period-cohort model in both hypopharyngeal and esophageal squamous cell carcinoma. The cohort effect decreased from mid-cohort 1903 gradually and increased from mid-cohort 1948 to mid-cohort 1973. Period effect increased persistently since time period 1983-1987. Age effect increased until age group 60-64 and then decreased slightly. Age effect was strongest, followed by cohort effect. The incidence trend of hypopharyngeal squamous cell carcinoma with second primary esophageal squamous cell carcinoma also increased. Interestingly, during time period 2003-2007, there were inverse incidence trends of hypopharyngeal squamous cell carcinoma with synchronous and metachronous second primary esophageal squamous cell carcinoma. The incidence trend of synchronous second primary esophageal squamous cell carcinoma increased more rapidly than previous periods and that of metachronous second primary esophageal squamous cell carcinoma decreased.
Conclusions
The same pattern of age-period-cohort model in both hypopharygneal and esophageal squamous cell carcinoma implies similar etiology and even mechanism of carcinogenesis. There is obvious shortening of difference of diagnostic time in hypopharyngeal squamous cell carcinoma with second primary esophageal squamous cell carcinoma during time period 2003-2007.
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