The TV veteran tells People magazine he has had a "kind of mind-boggling" shift in his health and is now in "near remission" from the illness, which has a nine per cent survival rate.
"The doctors said they hadn't seen this kind of positive result in their memory...," the Canadian tells the publication. "Some of the tumors have already shrunk by more than 50 per cent."
Though the 78-year-old still has several more more rounds of chemotherapy to go, he is keeping a positive mindset.
"I've got a couple million people out there who have expressed their good thoughts, their positive energy directed towards me and their prayers," he adds. "I told the doctors, this has to be more than just the chemo, and they agreed it could very well be an important part of this."
He adds, "I've got a lot of love out there headed in my direction and a lot of prayer, and I will never ever minimise the value of that."
Trebek shared news of his diagnosis with fans in March.