Very Hot Tea, Coffee Triple Esophageal Squamous Cell Cancer Risk, Study Finds

People who drink tea or coffee very hot face more than triple the risk of esophageal squamous cell carcinoma compared with those who drink it lukewarm, according to a large cohort study. The elevated risk applied to only one of the two main types of esophageal cancer; no link to temperature was found for esophageal adenocarcinoma.

The cancer epidemiology team at the University of Oxford's Nuffield Department of Population Health published the analysis in the International Journal of Cancer. Researchers linked survey responses on preferred drink temperature and daily cup intake from 977,282 participants in the UK Biobank and the Million Women Study to National Health Service medical records to track esophageal cancer cases. Follow-up averaged 14.2 years for the Million Women Study and 11.1 years for the UK Biobank. Over that period, 2,348 esophageal cancer cases were identified, including 1,045 squamous cell carcinomas and 1,303 adenocarcinomas.

Compared with those who preferred their drinks "warm," the risk of squamous cell carcinoma was about twice as high among those who chose "hot" and 3.17 times higher among those who chose "very hot." Consumption frequency acted separately. After controlling for temperature, those drinking six or more cups a day faced a 71% higher risk than those drinking fewer than six. About 15% of participants chose "very hot," while slightly fewer than half reported drinking six or more cups a day. Whether milk was added made no difference to risk.

Repeated thermal injury is cited as the mechanism. When hot liquid repeatedly irritates the esophageal lining, inflammation and regeneration cycle, raising the likelihood of cellular mutation, researchers said. In 2016, the International Agency for Research on Cancer classified beverages consumed above 65 degrees Celsius as probably carcinogenic to humans, in Group 2A. IARC data show 604,000 esophageal cancer cases worldwide in 2020, with 544,000 deaths. The agency expects annual cases to rise more than 50% by 2040. A 2019 American Cancer Society study that followed about 50,000 residents of Iran's Golestan province also found a 90% higher risk of squamous cell carcinoma among those drinking 700 milliliters or more a day at temperatures above 60 degrees Celsius.

The findings come with limits. Researchers did not measure actual beverage temperatures with a thermometer, relying instead on participants' subjective answers. Because the study was observational, causation cannot be established. Absolute risk is also low. In the United States, about 85% of esophageal cancers are adenocarcinomas, making the results difficult to apply directly. In Britain, esophageal squamous cell carcinoma is the 14th most common cancer, accounting for about 2% of all new cancer cases. Keren Papier, a senior nutritional epidemiologist at Oxford who led the study, said it is the largest of its kind to date and adds evidence supporting a link between hot drinks and this cancer type. The team estimated that lowering beverage temperatures in Britain could prevent 14% of new esophageal squamous cell carcinoma cases, while noting that managing already-known risk factors such as smoking and drinking must go hand in hand. If a drink is hot enough to scald the mouth, it is better to let it cool than to swallow it right away.