Dave Coulier, who played the character of Joey Gladstone on the hit sitcom Full House, has been diagnosed with a “very aggressive” form of Stage 3 non-Hodgkin’s lymphoma.

Coulier revealed his cancer diagnosis in an interview with People on Wednesday (Nov. 13), explaining that he got the news last October. He also spoke about his battle with the disease on a new episode of his Full House Rewind podcast.

The actor’s diagnosis was unexpected, he says, and came after a visit to the doctor to address some swollen lymph nodes following an upper respiratory infection.

People reports that Coulier’s doctor ordered PET and CT scans and a biopsy, which ultimately returned the results that he had “non-Hodgkin’s lymphoma,” and that it was “called B cell and it’s very aggressive.”

Coulier was shocked by the news. “I went from ‘I got a little bit of a head cold’ to ‘I have cancer,’ and it was pretty overwhelming,” he relates. “This has been a really fast roller coaster ride of a journey.”

The actor, who is 65 years old, made plans with his family and medical team to face the disease “head-on,” and he started chemotherapy just two weeks after being diagnosed. He also says that there was good news amid the difficult experience of receiving a cancer diagnosis: His bone marrow test came back negative, meaning that the cancer had not spread there.

“At that point, my chances of curable went from something low to 90 percent range. And so that was a great day,” he details.

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According to the Mayo Clinic, B cell lymphoma is a rare form of cancer that often presents as hard bumps underneath a person’s skin. The Cleveland Clinic notes that this form of the disease is often aggressive, but that prognosis varies widely based on an array of factors, including whether or not the cancer has spread to other parts of the body beyond the lymphatic system.

Six months into his chemo treatments, Coulier is remaining positive and taking things one day at a time, he tells People.

“I have my good days. I have my bad days,” he relates. “Some days are nauseous and dizzy, and then there’s other days where the steroids kick in, and I feel like I have a ton of energy. I actually just skated yesterday with some friends in Detroit. We just went and skated around and shot pucks, and it was wonderful just to be out there doing something that I love and just trying to stay focused on all the great stuff that I have in my life.”

Coulier played the role of Joey on Full House from 1987-1995.