MICHAEL DOUGLAS reveals his grueling cancer treatment after he was misdiagnosed 3 times in a white knuckle confessional.

As THE ENQUIRER reported extensively Douglas, now 69,  was diagnosed in 2010 that he had stage four cancer.

Now, Douglas has opened up, speaking to a group pf physicians at the International Federation of Head and Neck Oncologic Societies 5th World Congress in New York City after flying in from Comic-Con.

"When I learned that I had stage-four cancer, I'm pretty sure that my eyes rolled into the back of my head," Douglas confessed.

 "From the little I knew, this wasn't good. And I think that was probably the scariest moment I faced."

Douglas revealed he was actually misdiagnosed three times, after experiencing gum pain behind his molars.

When a CAT scan confirmed docs’ suspicions it was cancer, Douglas sought treatment at the Memorial Sloan Kettering Cancer Center in New York City.

"I went through seven weeks of radiation and chemotherapy, which somehow seemed very accurately mapped to the seven circles of hell," he vividly recalled.

"Each week I sank a little lower and I felt a little — no, I felt a lot worse."

Douglas also opted to not to have a feeding tube in his stomach.  "(The tube) would have had consequences for swallowing and taste later on," he explained.

Rgeardless,  Douglas dropped 40 pounds as his pals feared the worst.

"The doctors and nurses at Sloan Kettering had warned me not to expect to feel great the moment those seven weeks were over — that there would be another five weeks of feeling pretty awful until I could even hope to improve," Douglas said.

 "All of that was enormously important. Like a soldier, I prepared for battle. … It was my job to toughen up and get ready for the treatment and later on for my recovery, and that's what I was able to do."