Martin has battled epilepsy as the result of the tumours, and also revealed on Loose Women earlier this year that he was born with three kidneys.
While in agony on the Channel 4 show tonight due to cuts on his feet and legs, Martin decided to reveal his personal health story.
As he joined his fellow campmates around the fire, Martin revealed that after his operation, the one thing that “saved” him was EastEnders.
He explained: “When I came out of the operation, I could only see out of one eye, I couldn’t walk on one leg.
“I’d be standing still and wanting to walk over one way, but I’d walk over the other way.
“But the thing that saved me, absolutely saved me, was EastEnders.”
Martin revealed he feared remembering his lines, but portraying a lively character brought him back to life.
He continued: “Because, before I went to EastEnders, I didn’t even know if I could remember lines.
“And then when I turned up and had to play… I had to do the character of Steve Owen.
“Steve Owen was so full of life. He was so full of charisma and confidence, that that kind of helped me.”
Following the show, Martin posted a snap to his 117,000 Instagram followers and 187,000 Twitter followers.
In the post, Martin revealed he had lost a huge amount of weight, writing: “Before and after #celebrityisland. 2 1/2 stone!!!”
Martin’s fans instantly replied to the singer, with one teasing: “@realmartinkemp I’ve got a spare 2.5 stone you can have, lovely.”
“@realmartinkemp You had nothing on you anyway!! Wowser!!!” posted another.
A third added: “@realmartinkemp It’s been great watching you and the rest of the gang #theteamworks.”
“You were our favourite. Well done, you were classy throughout. Enjoy being with your family,” wrote another.
A fifth asked: “Martin you’re still a fabulous role model. We should see more of you on TV. Will you be eating bugs next?”
Martin was one of just seven celebrities who made it to the end of the show.
Next week’s final episode will see all of the islanders reunited back home to tell their own version of events.