HOWARD STERN longtime cohost ROBIN QUIVERS reveals year-long battle with cancer.

Quivers had been absent from the SiriusXM show's studio for a year.

NBC News reported that in  May of 2012, Quivers said she would be undergoing "a procedure" to remove a tumor on her bladder, 

During his first show sans his long time sidekick Stern said, "Doing a show without Robin is like cutting off my left arm. Or my right arm. Or maybe both."

"She was my backbone, you understand," Stern said. "Where I would lose courage, Robin always had the courage. She always is the brave one. Always the brave one with me. I could go to her, and I could always rely on her."

Stern has said multiple times that he would not continue the show without Quivers.

When she announced she was having her cancer  procedure, Stern said, "I'll f—ing kill you if you have cancer. I'm not doing the show without you … I'm quitting if you're not doing the show."

Stern Tweeted today, "I thought she was a goner," noting that he still gets chills listening to her story.

Happily, Robin says she's now cancer free after docs removed a tumor the size of a grapefruit.