Coffee, Tea, and Fatal Oral/Pharyngeal Cancer
Abstract and Introduction
Abstract
Epidemiologic studies suggest that coffee intake is associated with reduced risk of oral/pharyngeal cancer. The authors examined associations of caffeinated coffee, decaffeinated coffee, and tea intake with fatal oral/pharyngeal cancer in the Cancer Prevention Study II, a prospective US cohort study begun in 1982 by the American Cancer Society. Among 968,432 men and women who were cancer free at enrollment, 868 deaths due to oral/pharyngeal cancer occurred during 26 years of follow-up. Cox proportional hazards regression was used to estimate multivariable-adjusted relative risk. Intake of >4 cups/day of caffeinated coffee was associated with a 49% lower risk of oral/pharyngeal cancer death relative to no/occasional coffee intake (relative risk = 0.51, 95% confidence interval: 0.40, 0.64) (1 cup/day = 237 ml). A dose-related decline in relative risk was observed with each single cup/day consumed (Ptrend < 0.001). The association was not modified by sex, smoking status, or alcohol use. An inverse association for >2 cups/day of decaffeinated coffee intake was suggested (relative risk = 0.61, 95% confidence interval: 0.37, 1.01). No association was found for tea drinking. In this large prospective study, caffeinated coffee intake was inversely associated with oral/pharyngeal cancer mortality. Research is needed to elucidate biologic mechanisms whereby coffee might help to protect against these often fatal cancers.
Introduction
Oral/pharyngeal cancer is among the 10 most common cancers in the world, though less common in the United States where in 2012 an estimated 40,250 new cases and 7,850 deaths are expected to occur. Early stage disease is highly treatable with 82% 5-year survival. However, >60% of patients do not seek medical attention until their cancer has advanced to regional or distant stages; in these cases, long-term survival is poor at 56% and 34%, respectively. Men are more than twice as likely as women to develop and die from cancer of the oral cavity or pharynx.
The strongest risk factors for oral/pharyngeal cancer are tobacco and alcohol use. Human papillomavirus (HPV), particularly HPV type 16, one of the strains which cause cervical cancer in women, is also associated with increased risk of oral/pharyngeal cancer. Limited evidence exists for a role of diet and nutrition in the etiology of cancers of the mouth and pharynx. Coffee, one of the most commonly consumed beverages worldwide, contains a variety of anitoxidants, polyphenols, and other biologically active compounds that may help to protect against development or progression of cancer. Nine case-control and 1 prospective cohort study reported statistically significant inverse associations between coffee consumption and incident oral/pharyngeal cancer. A pooled analysis of unpublished, retrospectively collected data and a meta-analysis of published studies, mostly case-control, estimated between 35% and 40% lower relative risks for highest versus lowest daily intakes. Two studies did not find any association between coffee drinking and oral/pharyngeal cancer, though one, a US cohort study, did find a lower risk of pharyngeal cancer related to hot tea consumption.
Few studies have examined caffeinated and decaffeinated coffee separately, perhaps because of limited data on decaffeinated coffee, which is consumed less frequently and in smaller amounts than caffeinated coffee. However, a pooled analysis of both types reported an inverse association with caffeinated, but not decaffeinated, coffee intake. Because the decaffeination processes may alter the chemical constitution of coffee apart from caffeine extraction, it is possible that risks associated with caffeinated and decaffeinated coffee might differ. We undertook an analysis of caffeinated coffee, decaffeinated coffee, and tea intake as related to fatal oral/pharyngeal cancer in the American Cancer Society Cancer Prevention Study II, taking into account the potentially confounding effects of smoking, alcohol use, and other demographic, lifestyle, and dietary factors.