The 45-year-old actress was officially diagnosed with breast cancer in February 2015. Doherty now says that the disease has spread to her lymph nodes.
She has undergone three out of eight rounds of chemotherapy thus far and says she'll do radiation once the chemo has been completed. In May, Doherty underwent a single mastectomy.
"When I got back from surgery, [Bowie] again was kind of right in this area," Doherty says, gesturing towards her right side. "Then when I had my first chemo, she would sniff my entire body up and down. And she was always protective before, but she has become this crazy, protective dog. It's hard to get close to me when she's around."