The 90210 star was first diagnosed in August 2015, prompting her to undergo chemo and radiation, and later a mastectomy. Stage four cancer, however, is the most advanced form of the disease, meaning it has spread beyond the breast, underarm and internal mammary lymph nodes.
Still, despite the severity of her condition, Shannen has remained committed to her role on the BH90210 reboot. In fact, after her co-star Luke Perry died of a stroke last year, she felt she owed it to him to push through.
"It's so weird for me to be diagnosed and then somebody who was, you know, seemingly healthy to go first," she said. "It was really, like, shocking. And the least I could do to honour him was to do that show.”
Shannen also hopes that this fighter mentality inspires others battling similar diagnoses.
"It's a hard one because I thought when I finally do come out I would have worked and worked 16 hours a day and people can look at that and say, 'Oh my God, she can work and other people with stage 4 can work,'" she continued. "Our life doesn't end the minute we get that diagnosis. We still have some living to do."