How Melissa Gilbert Is Honoring Michael Landon, Patrick Swayze After Witnessing Their Deaths to Pancreatic Cancer (Exclusive)

Melissa Gilbert doesn’t use the word hate often, but when it comes to cancer — especially pancreatic cancer — she has no problem saying she hates it because the disease has “taken so many people from my life.”

Two of those were her Little House on the Prairie co-star Michael Landon and Gilbert’s longtime friend, Patrick Swayze, who both died from pancreatic cancer.

“We read about it, we hear about it from a distance, but until it touches you close to home, which it did with me, I personally did not realize how brutal it can be,” she tells PEOPLE.

Pancreatic cancer ranks as the third leading cause of cancer-related deaths in the U.S., according to the National Cancer Institute. It is rarely curable and has a five-year survival rate of less than 13%. Because there are so few symptoms in its early stages and there is no screening or test, the cancer is usually not detected until in more advanced stages, making it one of the most deadly cancers.

“It is really a brutal and pernicious disease,” Gilbert says. “To me, it feels like a tornado. You have no warning. It’s just there and the survival rate is virtually nil.”

The Little House on the Prairie star, 60, recalls how difficult it was to witness her costar Michael Landon — who played patriarch Charles Ingalls on the show — fight the disease before his death in 1991. Landon was a dear friend and father figure to Gilbert over the years and she says watching him deteriorate from the disease was shocking.

“I’d seen Michael have meningitis, I’d seen him with broken bones, I’d seen him with a lot of illnesses over the course of our time together. But this took him and decimated him so fast,” she says.

“This man was the epitome of physical wellbeing,” she continues. “I always described him as an upside down triangle, so strong, in such great shape, so healthy. And to see it happen so quickly and so almost violently, it felt like an enemy I wanted to defeat.”

Gilbert says it was just as hard to watch her longtime friend Patrick Swayze’s battle the disease. The Dirty Dancing actor died in 2009, at the age of 57 from pancreatic cancer.

“Literally nothing has brought this man down and this is going to do it?” Gilbert says. “He was able to fight for a lot longer than Michael Landon was able to. But still…You see them before and you see the pictures of them as they’re going through it and it is devastating.”

“This is the thing that killed two of the strongest, most extraordinarily extraordinary physical specimens of men I’d ever known in my life,” she says of Landon and Swayze. “Athletic, talented, I mean, you name it. To me, these guys were pillars, almost like superheroes. And to see something like that take them the way it did…And it’s not just the person going through it. I’m watching a whole family suffer along with both of these men as they are suffering in a way that is indescribable.”

Now, through her lifestyle brand Modern Prairie, Gilbert is teaming up with the Pancreatic Cancer Action Network (PanCAN) to raise money and awareness for the charity, which funds research, provides patient/caregiver support, conducts community outreach and advocates for increased federal research funding for those affected by the disease.

In honor of November’s Pancreatic Cancer Awareness Month, the actress is launching a special capsule collection, including women’s and children’s bonnets, pocket squares, signature pie carrier, throw blanket, and tote bag. The products — debuting October 14 — all feature a purple striped and purple calico fabric that Gilbert created as a nod to the official color for pancreatic cancer awareness.

“y work with PanCAN is a passion of mine and important to me because of the people I’ve lost — whom I’ve known and loved — to pancreatic cancer,” Gilbert says, noting that all proceeds from the collection will support the charity.