Asian case-control studies have shown a strong relationship between the development of squamous cell carcinoma (SCC) of the esophagus and alcohol consumption combined with inactive aldehyde dehydrogenase-2 (ALDH2*1/*2), less-active alcohol dehydrogenase-1B (ADH1B*1/*1), high mean corpuscular volume (MCV), and self-reported facial flushing in response to alcohol. However, little is known about whether these risk factors prospectively influence cancer development in cancer-free alcoholics. Between 1993 and 2005, 808 Japanese alcoholic men diagnosed as cancer-free by an initial endoscopic screening examination received follow-up examinations ranging from 1 to 148 months (median, 31 months) later, and SCC of the upper aerodigestive tract was diagnosed in 53 of them (esophagus in 33 and oropharyngolarynx in 30). Cox proportional hazards analysis showed that the age-adjusted relative hazard for SCC was 11.55 [95% confidence interval (95% CI), 5.73-23.3] in ALDH2*1/*2 heterozygotes compared with ALDH2*1/*1 homozygotes, 2.02 (95% CI, 1.02-4.02) in ADH1B*1/*1 homozygotes compared with ADH1B*1/*2 heterozygotes or *2/*2 homozygotes, 2.64 (95% CI, 1.49-4.67) in patients with flushing compared with those who had never experienced flushing, 2.91 (95% CI, 1.63-5.20) in those with an MCV >or= 106 compared with those with an MCV < 106, 2.52 (95% CI, 1.22-5.22) in those who smoked >or=30 cigarettes per day compared with those who smoked 0 to 19 cigarettes per day, 7.26 (95% CI, 3.99-13.23) in those with esophageal dysplasia compared with those without distinct iodine-unstained lesions >or=5 mm, and 0.28 (95% CI, 0.09-0.85) in those with body mass index >or= 23.2 (highest quartile) compared with those with body mass index < 19.0 (lowest quartile). These predictors are useful for selecting appropriately patients for careful follow-up examinations.