Lavigne has been battling the illness since late last year, and has remained in good spirits while documenting her recovery. In late June, she told Good Morning America that she was about halfway done with her treatment and expecting to make a full recovery.
"I sat there in my bed and watched [fan videos showing their support for her] and I cried through the whole thing and honestly I felt very loved," she said. "It sounds silly, but I really did feel my fans through the process."
Meanwhile, as Lavigne's health improved, the singer announced her separation from husband of two years, Nickleback frontman Chad Kroeger, in September.
"It is with heavy heart that Chad and I announce our separation today," she wrote on Instagram at the time. "Through not only the marriage, but the music as well, we've created many unforgettable moments. We are still, and forever will be, the best of friends, and will always care deeply for each other."