Colon cancer patients who enjoy a few cups of coffee a day appear to survive their cancer better and they're less likely to die early than non-coffee drinkers, researchers reported Monday.
It's the latest in a series of studies showing the benefits of coffee, which can lower the risk of diabetes, Parkinson's and cancer. This is the first one to show it may help patients recover better, and should come as welcome news to colon cancer patients who worry if they can safely enjoy coffee.
"What we found in this slightly less than 1,000 patients is that those who drank coffee regularly had a better disease-free survival, meaning they had a lower rate of having their cancer recur or of dying," said Dr. Charles Fuchs, director of the Gastrointestinal Cancer Center at the Dana-Farber Cancer Institute in Boston.
The colon cancer patients have been filling out daily diaries with details of what they eat and how much they exercise. They've all been diagnosed with Stage III colon cancer, which has spread to nearby lymph nodes but which hasn't spread to the rest of the body yet.
All the patients had surgery and chemotherapy. Those who drank four or more cups of coffee a day were 42 percent less likely to have their cancer come back than non-coffee drinkers. They were 33 percent less likely to die of their cancer or of anything else during the study, the team reports in the Journal of Clinical Oncology.
Two or three cups of coffee a day had a somewhat slighter benefit.
By the way, other caffeinated drinks such as soda didn't have the same effect. "People who consumed two or more sugar sweetened beverages a day have a poorer outcome," Fuchs said. Tea and decaffeinated coffee did not have the same benefit, although not very many people drank tea or decaf exclusively so it's hard to say.
And the researchers did not ask how people took their coffee - black, with sugar, or as a latte. That's a question to ask in follow-up, Fuchs said.
Fuchs said there were two reasons for the study: Colon cancer and diabetes seem to have similar risk factors, and the demand among patients for something they can do to help recover from their cancer.
"We have actually in this cohort found that obese patients do worse, sedentary patients do worse, patients who exercise did better and patients who avoided a Western-pattern diet or a high-glycemic-load diet did better," Fuchs said.
"The risk factors for adult onset type-2 diabetes seemed to influence the outcome of colon cancer patients," Fuchs added. "The preponderance of evidence is that people who drink coffee have a lower risk of diabetes."
Now the question is what is it about coffee that's helping? Fuchs said it could be antioxidants or other compounds in coffee, it could be effects on metabolism, on the microbes living in the gut, or something else.
These are not the kinds of studies that drug companies will pay for, so the research is funded by the federal government's National Cancer Institute.
"The bottom line is that there are patients for whom the cancer recurs despite our best efforts and we wanted to see what diet and lifestyle could modify that risk," Fuchs said.
"A majority of patients do believe that these things matter. The problem is we haven't been able to give them answers that are based on scientific investigation."
Fuchs says it's too soon to prescribe coffee to cancer patients, or to encourage non-coffee drinkers to start. He wants other teams of scientists to try and match his findings first.