The former "Beverly Hills, 90210" star wrote on Instagram on Friday: "Last day of chemo. Exhausted."
"Now that I'm done with chemo and radiation, the waiting game is here," Doherty, 45, continued. "Waiting for test. Waiting to see if I'm clear or not. Waiting for reconstruction. Waiting."
Doherty concluded, "I think when one gets cancer, they are always waiting to a certain extent. To those who know ... I'm waiting with you. #cancerslayer."
In 2015, Doherty went public with her breast cancer diagnosis when she sued her former business managers for allowing her health insurance to lapse. That case reportedly was settled last August.
Doherty underwent a mastectomy, and when she learned that the disease may have spread to her lymph nodes, she began chemotherapy.
“I think what’s beautiful and hard and interesting about cancer is that it tears you down and builds you, and tears you down and builds you and it remakes you so many different times," she said.
"So the person I thought I was supposed to be or was going to be or who I thought I was six months ago is now somebody completely different," Doherty added. "And I realize ‘Wow, I really thought that I was so brave and so gracious this entire time and really I was just hiding.'"