"I do believe without a doubt, unquestionably, that chewing is what gave me cancer," he said.
During the broadcast, Schilling issued a warning to smokeless tobacco users.
"It's like being given a death sentence without committing a crime," Schilling said.
The cause of ballplayers against smokeless tobacco deepened in June, when Hall of Famer Tony Gwynn died after battling cancer of the salivary gland. After Gwynn's passing, Commissioner Bud Selig and Tony Clark, the executive director of the Major League Baseball Players Association, both expressed a desire to end the use of tobacco in baseball.
"It will be a subject they'll discuss during the next collective bargaining," Selig said during the All-Star break. "I understand that individuals have a right to make their own decisions. I hope we're successful, because the Tony Gwynn story was a heartbreaking, awful story.
"I feel very strongly about this, just as I did 10, 15 years ago. The one thing I personally assume as Commissioner is that we're responsible for the health of our players. I believe that. Some may think that's naive, but I don't think so."
Schilling, who pitched in the Majors for 20 years, said that he used smokeless tobacco for 30 years and that he had been unable to kick the habit despite pain associated with it.
"It's a dangerously addictive habit that I wish I had never done," Schilling said.
Schilling had a heart attack in 2011 and required surgery to place a stent in one of his arteries, and he told WEEI on Wednesday that he has lost 75 pounds during his bout with cancer.
"I am in remission," Schilling said. "[However], I don't have any salivary glands. I can't taste anything and I can't smell anything."