Frequent drinking associated with risk of head and neck cancer: NHRI study
November 25, 2019
Higher frequency and amount of alcohol use are associated with an increased head and neck cancer risk, according to the results of a study conducted by the National Health Research Institutes’ National Institute of Cancer Research and by National Cheng Kung University Hospital. The results of this study were published in Cancer Epidemiology, Biomarkers, and Prevention.
Head and neck cancer — including cancers of the oral cavity, oropharynx, hypopharynx, and larynx — is one of the common cancers occurring among men in Taiwan. The incidence and mortality rates of head and neck cancer among Taiwanese men have continued to increase. Currently, head and neck cancer ranks fourth for both cancer incidence and mortality among Taiwanese men.
The majority of head and neck cancer cases in Taiwan can be attributed to the use of alcohol, betel quids, and cigarettes. Efforts by the government and public health organizations have decreased the prevalences of cigarette smoking and betel quid chewing. After the enactment of the Tobacco Hazards Prevention Act by the Taiwan government in 1997, the prevalence of cigarette smoking among men decreased from 55.1% in 1996 to 26.4% in 2017. Similarly, the prevalence of betel quid chewing among men decreased from 17.2% in 2007 to 6.1% in 2017. In contrast, the prevalence of alcohol drinking in Taiwan has been increasing.
The major carcinogen of alcohol is acetaldehyde generated through alcohol metabolism. Acetaldehyde associated with consumption of alcoholic beverages is listed by the International Agency for Research on Cancer as a Group 1 carcinogen, which means that there is sufficient evidence to indicate that it is carcinogenic to humans. Approximately half of the Taiwanese population are unable to metabolize acetaldehyde efficiently due to a variation in the ALDH2 gene. These individuals, after drinking alcohol, are likely to develop symptoms such as facial flushing and tachycardia. They are also more likely to develop alcohol-related cancers due to inefficient metabolism of acetaldehyde.
In the National Health Research Institutes study, hypopharyngeal cancer showed the strongest association with alcohol use, followed by oropharyngeal cancer and laryngeal cancer. Overall, 22% of the head and neck cancer cases were associated with alcohol drinking. The results also showed that the alcohol-metabolizing genes, ADH1B and ALDH2, influenced the risk of head and neck cancer. Individuals with the slow enzyme activity genotypes of these two genes had the highest head and neck cancer risk associated with alcohol drinking. In this group of individuals, about half of the head neck cancer cases were associated with alcohol use. The study also showed that alcohol drinkers needed to quit drinking alcohol for more than 10 years to lower the risk of head and neck cancer to the level of never drinkers. The results of this study were published in Scientific Reports in August 2017.
The oral cancer research group also investigated the impact of alcohol drinking on the survival of head and neck cancer patients. The results showed that head and neck cancer patients who were alcohol drinkers had worse survival than those who were non-alcohol drinkers. The main reason for the poorer survival of alcohol-drinking head and neck cancer patients was a higher percentage of late-stage diagnosis. This suggests that alcohol not only may induce the development of head and neck cancer but also may promote its progression and metastasis; however, confirmation of this would require additional study.
Studies have linked the association between alcohol and other cancers as well, including esophageal cancer, colorectal cancer, breast cancer, and liver cancer. With the increasing consumption of alcohol in Taiwan and the high percentage (~50%) of the Taiwanese population with compromised acetaldehyde metabolism, the incidence and mortality rates of alcohol-related cancers will likely increase. Therefore, reducing alcohol consumption in Taiwan in order to decrease the occurrence of alcohol-related cancers should be a public health concern.