Subsite-specific risk factors for hypopharyngeal and esophageal cancer (Japan)

Objectives: To clarify subsite-specific risk factors for hypopharyngeal and esophageal cancers (HC and EC), we concluded a hospital-based case-referent study in Nagoya, Japan. Methods: Subjects comprised 346 male cases with cancer of the hypopharynx (n = 62) or esophagus (upper [U-EC] 53, middle [M-EC] 159, lower [L-EC] 72), and 11,936 male referents free from cancer among first-visit outpatients aged 40-79 years in 1988-1997. Of histological confirmed cases, 93% comprised squamous cell carcinoma. Odds ratios (ORs) were estimated by a logistic regression model with adjustment for potential confounding factors. Results: Cigarette smoking increased the OR for M-EC, and alcohol drinking elevated the ORs for all subsites. The trend of ORs for combined cases of M- and L-EC tended to increase with number of cigarettes (p = 0.056), and a decreasing trend of the ORs was found with years after quitting smoking (p = 0.006). The ORs for smoking with drinking were multiplicatively greater than those for smoking or drinking in combined cases of HC and EC. In contrast, daily raw vegetable consumption lowered the ORs for all subsites. Conclusions: This study suggests that the magnitude of risk with smoking is stronger for M-EC within the esophagus, and drinking increases the risk at any subsite.