Shannen Doherty shares a 'truthful' look at the reality of cancer treatment

Shannen Doherty is sharing the reality of her cancer battle.

The actress, who was first diagnosed with breast cancer in 2015, revealed last year that the disease had returned, this time as stage four.

In an Instagram post Thursday, Doherty wrote that she wanted to be open about her "personal journey" in hopes of educating the public and encouraging people to be vigilant about their health.

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"In 2015 I got diagnosed with breast cancer. I had a mastectomy and did chemo and radiation. I had many nose bleeds from the chemo. Not sure if any of you experienced this. I also was beyond tired," she wrote. "I cheered myself up by putting on funny pajamas that my friend Kristy gave me. Did they actually cheer me up? Yes!!"

"I looked ridiculous and in that ridiculousness, I was able to laugh at myself," she continued. "Finding humor helped get me thru what seemed impossible. I hope we all find humor in the impossible. #breastcancerawareness"

Doherty, 50, recently told ABC News that work has become "even more fulfilling" in the wake of her diagnosis. The actress has two Lifetime movies premiering this month.

"A lot of people who get diagnosed with stage four, they sort of getting written off. It's assumed that they cannot work or they can't work at their full capacity. And that is not true," she said. "That is something that I would really like for people to sort of stop assuming, and give us a chance to prove them wrong."

When someone is diagnosed with stage four breast cancer, it means that the disease has spread to other areas of the body, according to the National Cancer Institution. The Susan G. Komen organization reports that new treatments have improved the survival rates for those diagnosed with stage four, or metastatic breast cancer. According to the group, about one-third of women who have been diagnosed with stage four breast cancer will live at least five years past their diagnosis, though some will live for 10 or more years.