Known for her work on the sitcoms "Rhoda" and "Valerie," Harper, 74, announced in March she had been diagnosed with an aggressive form of brain cancer and given as few as three months to live.
But her oncologist said in September Harper is "pretty close to a remission. It defies the odds."
Since announcing her diagnosis, Harper has published a memoir, taped an episode of "Hot in Cleveland" with her former "Mary Tyler Moore Show" cast members and starred in a TV movie.
She joined the "Dancing with the Stars" cast last month and is the third celebrity eliminated from the competition, following Keyshawn Johnson and Bill Nye "the Science Guy."
"It has been absolutely wonderful," Harper said after receiving a standing ovation from the studio audience Monday night. She went on to say competing on the show was an "opportunity for me to carry a message to folks... 'Keep on keepin' on.'"
Harper and MacManus were given the boot because of their combination of low judges' scores and viewer votes.
Still in the running for the coveted mirror-ball trophy are actresses Elizabeth Berkley, Leah Remini and Amber Riley, singer Christina Milian, "Jersey Shore" alum Snooki Polizzi, singer-actor Corbin Bleu, comedian Bill Engvall, actor Brant Daugherty and reality TV personality Jack Osbourne.