Esophageal, apparently. Though most of the items I've seen mention his smoking, that's far from the only risk factor--acid reflux accounts for thirty percent of cases, and drinking and overweight are associated with both GERD, and cancer of the esophagus. Sadly, the five year survival rate for all esophageal cancer is only 17%, and 2/3 of those with even localized tumors don't make it that long. (Though Hitch is younger than the typical victim, which may help his chances.)
If it weren't blasphemous, I'd suggest saying a prayer for him.