Alcohol drinking is an established risk factor for the incidence of oral and pharyngeal cancer (OPC) [1]. A meta-analysis found that the pooled risk ratio for upper aerodigestive tract cancer, including OPC mortality, was 1.26 (95% confidence interval [CI] = 0.94–1.67) for light drinkers (≤ 12.5 g/day of ethanol), 1.79 (95% CI = 1.26–2.53) for moderate drinkers (12.6–49.9 g/day of ethanol), and 3.63 (95% CI = 2.63–5.00) for heavy drinkers (≥ 50 g/day of ethanol), compared to non/occasional drinkers [2]. In 2015, it was estimated that alcohol consumption accounted for 22.5% of OPC incidence and 21.9% of OPC mortality in Japan [3].

However, there is a lack of knowledge regarding the association between alcohol consumption and the prognosis of patients with OPC and existing evidence is conflicting [1], [4], [5], [6], [7], [8], [9], [10], [11]. Several studies have reported significant positive findings [4], [5], [6], [7], [9], [11] suggesting that active drinking, that is ≥ 120 g/ week ( ≥ 17.1 g/ day) of ethanol, is associated with increased mortality risk [5]. On the other hand, other studies have found no difference in mortality risk between active drinkers and non-drinkers after adjusting for a wider range of confounding factors, such as smoking status and cancer stage [8], [10].

Most previous studies are surveys from Europe [4], [5], [7], [8], [10] and examined up to 5 years of overall survival [4], [5], [6], [9], [11]. Drinking patterns between countries and regions differ due to cultural background, and no clear benefit from drinking cessation had emerged up to at least 10 years after stopping regarding the incidence of OPC [12]. It is important to draw attention to the effects of alcohol drinking on longer-term mortality. Therefore, using hospital-based cancer registry data, we evaluated the association between alcohol consumption and 10-year mortality among oral and pharyngeal cancer patients in Japan.