Dave Coulier Reveals He Has Stage 3 Non-Hodgkin Lymphoma: ‘I'm Going to Be Strong Throughout This’ (Exclusive)

The 'Full House' actor opens up to PEOPLE exclusively about his cancer diagnosis

Dave Coulier has been diagnosed with stage 3 Non-Hodgkin lymphoma.

The Full House actor, 65, tells PEOPLE exclusively he was diagnosed in October after an upper respiratory infection caused major swelling in his lymph nodes.

As his swelling increased rapidly, with one area growing to the size of a golf ball, he says his doctor advised PET and CT scans as well as a biopsy, which ultimately gave him news that changed his life.

“Three days later, my doctors called me back and they said, ‘We wish we had better news for you, but you have non-Hodgkin's lymphoma and it's called B cell and it's very aggressive,’” he recalls.

“I went from, I got a little bit of a head cold to I have cancer, and it was pretty overwhelming,” he says. “This has been a really fast roller coaster ride of a journey.”

Related: James Van Der Beek's Cancer Diagnosis

Upon learning of his diagnosis, Coulier says he and his wife Melissa Bring — along with some of his close friends in the medical field — immediately worked together to meet his diagnosis “head-on.”

“We all kind of put our heads together and said, ‘Okay, where are we going?’ And they had a very specific plan for how they were going to treat this,” he says, noting that a bright spot in his diagnosis was when his bone marrow test came back negative. “At that point, my chances of curable went from something low to 90% range. And so that was a great day.”

Two weeks into his diagnosis, Coulier says he immediately started chemotherapy. He shaved his head as a “preemptive strike,” and he opens up about his experience further on his podcast Full House Rewind with Marla Sokoloff.

“I started the podcast wearing a hat, and I said, I've always been a man of many hats, but this hat has special significance because a couple of weeks ago, I was diagnosed with non-Hodgkin's lymphoma,” he says of the debut episode where he opens up about his diagnosis. “That was really a conscious decision of, I'm going to meet this head-on, and I want people to know it's my life. I'm not going to try and hide anything. I would rather talk about it and open the discussion and inspire people.”

Throughout his cancer journey, Coulier says he is choosing to keep a positive outlook, especially for his wife and son Luc, who he reveals is expecting his first child. “I looked at how those words affected [Melissa] and I thought, you know what, I'm going to be strong throughout this, not just for me, but I'm going to be strong for her.”

As Coulier goes through this journey, he has been pulling inspiration from family members, many of whom also went through cancer. “I lost my mom to breast cancer. I lost my sister Sharon to breast cancer. She was 36 years old. I lost my niece, Shannon. She was 29 years old,” he says, adding that his older sister Karen is also going through cancer alongside him.

“I saw what those women in my family went through, and I thought to myself, ‘If I can be just 1/10th of a percent as strong as they were, then I'm going to be just fine,” he says.

Amid his treatments, he says that he’s been leaning on his sister Karen — and leaning into their shared humor — to keep his spirits up.

“My sister was a registered nurse, and so she's seen this from different optics than I have,” he explains. “She's been so supportive and she's funny. So we're making jokes about this. One of my jokes is in four short weeks I've gone from a Virgo to a Cancer. I'm a huge hockey fan. So when they said ‘You've got NHL,’ I thought, ‘I finally made it to the NHL.’”

“When I first got the news, I was stunned, of course, because I didn't expect it, and then reality settled in and I found myself remarkably calm with whatever the outcome was going to be,” he says. “I don't know how to explain it, but there was an inner calm about all of it, and I think that that's part of what I've seen with the women in my family go through. They really instilled that in me and inspired me in a way because they were magnificent going through what they went through, and I just thought, ‘I'm okay with this too.’ I've had an incredible life on a journey with incredible people around me and I'm okay. It does change perspective for sure.”

Coulier has already completed the first of six chemo treatments, and he’s taking everything day by day.

Related: Full House's Candace Cameron Bure, Dave Coulier and Andrea Barber Predict Where Their Characters Would Be Today (Exclusive)

“I have my good days. I have my bad days,” he says. “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 skated yesterday with some friends here 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.”

That includes preparing to be a grandpa: Coulier’s son Luc, 33, and his wife Alex are expecting a baby boy due in March. “I’ve got to teach him how to play hockey,” he says. “There’s a lot to look forward to."

Ultimately, in sharing his own story, Coulier hopes he can inspire others to get tested early.

“Take great care of yourself, because there's a lot to live for,” he advises fans. “And if that means talking with your doctors or getting a mammogram or a breast exam or colonoscopy, it can really make a big change in your life.”