The 50-year-old actor revealed he was diagnosed with prostate cancer in June 2014 during an interview on SiriusXM's The Howard Stern Show on Tuesday, and says early detection saved his life. His doctor was able to detect the cancer when he gave the comedian a Prostate-Specific Antigen (PSA) test during a yearly physical.
"If I hadn't gotten the test -- my doctor started giving it to me at 46 -- I still wouldn't know," Stiller said. "I wanted to talk about it because of the test, because I feel like the test saved my life."
The PSA test is a blood test used primarily to screen for prostate cancer, and measures the amount of prostate-specific antigen in a person's blood. The diagnosis came as a total shock to Stiller, given that the Zoolander star has no history of prostate cancer in the family.
"It came out of the blue for me. I had no idea," Stiller told Stern. "At first, I didn't know what was gonna happen. I was scared. It just stopped everything in your life because you can't plan for a movie because you don't know what's gonna happen."
Stiller shared he eventually had surgery to treat his cancer. In a blog post on Medium about his experience dealing with "mid-range aggressive" prostate cancer, he says he got a test back telling him he was cancer free on Sept. 17, 2014.
"As I learned more about my disease (one of the key learnings is not to Google 'people who died of prostate cancer' immediately after being diagnosed with prostate cancer), I was able to wrap my head around the fact that I was incredibly fortunate," Stiller writes. "Fortunate because my cancer was detected early enough to treat. And also because my internist gave me a test he didn't have to."
"As of this writing I am two years cancer free and extremely grateful," he adds.
Stiller has been married to actress Christine Taylor since 2000. The couple has two children, 14-year-old Ella and 11-year-old Quinlin.
ET spoke with Stiller at the New York City Zoolander 2 premiere in February, when he told us the secret to his enduring marriage, and talked about the unpredictability of life.
"I think you got to laugh," he told ET exclusively. "Because, you know, after a while, life is life you know? We all have to deal with what life throws at us, so you got to have a sense of humor about it. If you can share that, at the end, it makes a huge difference."