what warden,neo said is right
repeat ingestion of high temperature liquids will (overtime) lead to irreversible damage to the lining of the esophagus and a step to cancer is then very much closer.
(similar to how repeat reflux disease leads to Barrett's esophagus and then cancer)
(its likely a slow process and requires alot of repeated drinking of high temperature liquids, over probably 10 or more years)
there were a couple studies i think one of tea drinkers in Iran.
"Iran, Russia, and South Africa, ingestion of very hot foods and beverages (such as tea) has been associated with esophageal SCC. In one epidemiologic study, significantly more people in high-risk regions within Iran drank their tea at temperatures greater than 65ºC compared to low-risk regions (62 versus 19 percent) . Furthermore, inhabitants of high-risk regions drank approximately 2.5 times more hot tea than their low-risk counterparts."
TI Thermal irritation and esophageal cancer in northern Iran.
AU Ghadirian P
SO Cancer 1987 Oct 15;60 (8 ):1909-14.
The ingestion of hot food and beverages has repeatedly been postulated as a risk factor for cancer of the esophagus. Although several studies have been performed on the correlation of the consumption of hot tea and esophageal cancer, no research has heretofore documented, by actually measuring, the temperature at which the tea is consumed. Therefore, a tea temperature measurement study was carried out in the Caspian Littoral of Iran, where the frequency of esophageal cancer is the highest in the world. The study was conducted during a population-food-habits survey in 1968 to 1969, which was performed before statistics were available regarding the incidence rate or geographic distribution of this disease in the region. Ten years later, when the results of the Caspian Cancer Registry were analyzed, the data from this nutritional study was compared with the regional distribution of esophageal cancer. A geographic correlation exists between the frequency of consumption of hot tea and the incidence of esophageal cancer. Seventy-two percent of the people in the low-risk region of esophageal cancer drank their tea at the relatively moderate temperature of below 55 degrees C, compared with only 3% in the high risk region. More importantly, 62% of the adult population in the high-risk region, as opposed to 19% in the low-risk region, drank their tea at a temperature of over 65 degrees C. In addition to the thermal irritation of hot tea, the following considerations cannot be ignored: the carcinogenicity role of tannins; the cancer-promoting effect of phenols; and the absorption facilitating role of hot tea. Alcohol and tobacco, the most important risk factors for cancer of the esophagus in many countries, play a negligible role in the cause of this disease in northern Iran. In this region, nutritional deficiencies--a special diet for pregnant women composed of sour pomegranite seeds, black pepper, and garlic; consumption of bread contaminated with silica fibre; and ingestion of opium and opium dross--combined with long-lasting and daily thermal irritation of the esophagus with very hot tea play an important role in the development of this disease. The inhabitants of the high-risk area consumed roughly 2.5 times more tea than their counterparts in the low-risk area. In addition, the mean daily consumption of tea leaves per person (average) was 5.7 g and 3.8 g, respectively.
AD Unite de Recherche en Epidemiologie, Hotel-Dieu de Montreal, Canada.
some more, i didnt read these, but these studies should factor out the very risky behaviors for esophageal cancer: smoking and alcohol.
just 7 results on medline search
http://www.ncbi.nlm.nih.gov/sites/entre ... $=activity
http://www.ncbi.nlm.nih.gov/pubmed/1281 ... d_RVDocSum
Maté consumption and the risk of squamous cell esophageal cancer in uruguay.
Sewram V, De Stefani E, Brennan P, Boffetta P.
Promec Unit, Medical Research Council, Tygerberg, South Africa.
A retrospective hospital-based case-control study was carried out at the Oncology Institute of Montevideo, Uruguay, to investigate the role of maté consumption in esophageal cancer risk. The study included 344 cases with squamous cell carcinoma of the esophagus and 469 controls recruited between January 1988 and August 2000. Maté consumption was significantly associated with an increased risk of developing esophageal cancer and showed a clear dose response, with a relative risk of 2.84 [95% confidence interval (CI), 1.41-5.73] for those drinking more than 1 liter/day of maté as compared with nondrinkers. Subjects who self-reported drinking maté at a very hot temperature had an almost 2-fold increase in risk [odds ratio (OR), 1.87; 95% CI, 1.17-3.00] compared with those drinking warm to hot maté, after adjusting for cumulative consumption of maté. Maté amount and temperature were observed to have independent effects and, although no departure from multiplicativity was observed between the two covariates, those drinking more than 1 liter/day of maté at a very hot temperature had a 3-fold increase in risk (OR, 2.95; 95% CI, 1.30-6.74) compared with those drinking less than 0.5 liter/day of maté at a warm to hot temperature. Subjects with high cumulative exposure to maté in the presence of low alcohol and tobacco exposures presented a lower-risk estimate (OR, 1.52; 95% CI, 0.88-2.62), whereas those with high cumulative exposures to maté, alcohol, and tobacco presented a 7-fold increase in esophageal cancer risk (OR, 7.10; 95% CI, 3.75-13.46). The population-attributable fraction as a result of maté consumption was calculated to be 53%, of which the sole effect of amount and temperature was 14.8 and 12.6% respectively, and 14.9% was attributable to high maté consumption at high temperature.
http://www.ncbi.nlm.nih.gov/pubmed/1672 ... d_RVDocSum
BACKGROUND: The highest rates of esophageal squamous cell carcinoma (ESCC) in Brazil occur in Rio Grande do Sul, the most southern state, which has incidence rates of 20.4/100,000/year for men and 6.5/100,000/year for women. Exposure to carcinogenic polycyclic aromatic hydrocarbons (PAHs) through tobacco smoke and other sources may increase the risk of ESCC. The aims of the current study were to investigate the degree and sources of PAH exposure of the inhabitants of this region of southern Brazil. METHODS: Two hundred healthy adults (half smokers, half non smokers, half male and half female) were recruited, given a standardized questionnaire, and asked to provide a urine sample for measurement of 1-hydroxypyrene glucuronide (1-OHPG), a PAH metabolite). Urine 1-OHPG concentrations were measured using immunoaffinity chromatography and synchronous fluorescence spectroscopy and urine cotinine was measured using a dipstick test. We examined factors associated with 1-OHPG concentration using Wilcoxon tests and multiple linear regression. RESULTS: Urine 1-hydroxypyrene glucuronide (1-OHPG) was successfully measured on 199 subjects. The median (interquartile range) of urine 1-OHPG in the 199 participants was 2.09 pmol/mL (0.51, 5.84). Tobacco smoke exposure and maté drinking were statistically significantly associated with higher urine 1-OHPG concentrations in the multivariate linear regression model. CONCLUSION: Tobacco smoke and maté both contribute to high levels of benzo[a]pyrene exposure in the people of southern Brazil. This high PAH exposure may contribute to the high rates of ESCC observed in this population. The increased urine 1-OHPG concentrations associated with maté suggest that contaminants, not just thermal injury, may help explain the increased risk of ESCC previously reported for maté consumption.
http://www.ncbi.nlm.nih.gov/pubmed/3865 ... d_RVDocSum
Esophageal cancer has constituted a major public health problem in Uruguay, with age-adjusted death rates of 14.5 X 10(5) for males and of 3.8 X 10(5) for females. A case-control study was undertaken to ascertain the possible association of the local custom of drinking infusions of Ilex paraguariensis ("maté") with cancer of the esophagus, after controlling for well-known risk factors, such as alcohol and tobacco consumption. Two hundred twenty-six patients with esophageal cancer and 469 controls (control:case = 2.1) were interviewed at the time of admission or consultation at the Oncology Institute of Montevideo from 1979 through 1984. Males showed elevated risks of esophageal cancer associated with heavy tobacco [relative risk (RR) = 10.8] and alcohol (RR = 10.3) exposures. Among females, the independent effects of tobacco and alcohol were nonsignificant. Maté consumption had an independent effect in both males and females, with odds ratios of 6.5 and 34.6, respectively, for heavy users. Moreover, a well-defined dose response was evident in both sexes.