Shannen also uploaded a snap to Instagram of herself to standing in front of a large machine used for radiation therapy.
“This is Maggie. I've seen Maggie five days a week for what seems like forever,” she wrote.
“We have a love hate relationship. I love her because she's part of the life saving treatment I'm receiving. It's astounding how far we have come with technology. One day, Maggie will be retired and the cure will be found. Things like immunotherapy are the future but for now.... it's me and Maggie.
“I'm seeing her twice tomorrow so that I can wrap this phase up faster. Goodnight sweet Maggie. See ya tomorrow. #cancerslayer.”
Despite her grueling battle, the star is trying to remain upbeat and active, posting videos of herself doing a dance workout with her trainer.
“Radiation is tiring. It builds up within you and sometimes one just struggles to keep their eyes open. You can see how tired I am here but I'm still moving!! Any movement is so good during treatment, not just for the body, but for your mind as well. #cancerslayer”.