Just passing along some recent info:
A study, published in the American.Journal of Epidemiology, finds people who drink 4 of caffeinated coffee a day have half the risk of dying from oral/ pharyngeal cancer as people who drink it either occasionally or not at all. The study began in 1982, Cancer Precvention Study II, by the American Cancer Society. Researchers were able to examine 968,432 men and women, none of whom had cancer at the time of enrollment. There is more to the study, if you care to look into.
I drank as much coffee, so I must have been in the other 50 percent. I hope they will find it will have a positive effect in chemo prevention for recurrences, in the future, if they do research on that too.