In a frank discussion, Quivers, 61, explained why she's been absent from the studio (and broadcasting from home) since mid-2012. She revealed that she'd undergone surgery, chemotherapy and radiation treatment for a grapefruit-size tumor discovered in her uterus.
Quivers got emotional as she remembered the talk she had with Stern after getting the diagnosis – when doctors talked about "prolonging" her life, rather than "saving" it.
"Before that conversation was over, I realized how much I meant to you," she told the America's Got Talent judge.
While Stern, 59, was being strong for his friend and broadcasting partner of 32 years, deep down he was shattered, and admitted that he began making funeral arrangements.
"I gotta be honest," Stern said candidly, "I thought she was a goner."
But a new set of doctors had a more hopeful prognosis, and after a 12-hour surgery to remove the mass, Stern visited Quivers in the hospital, bringing her a basketful of ChapStick and gum – two things she'd need as she began chemo and radiation – and a self-portrait, which he placed by her bedside so he could watch over her.
Quivers responded well to the treatments and didn't experience the draining side effects, like nausea and tiredness – she went out to dinner every night, and the only sign that she was undergoing chemo was that she lost her trademark dreadlocks.
Quivers only missed three shows during this time, but if she hadn't been able to return, Stern confessed that it would have been the end of his show.
"She was my backbone, you understand. Where I would lose courage, Robin always had the courage," he said. "She always is the brave one. Always the brave one with me. I could go to her, and I could always rely on her."