Valerie Harper, Fighting Cancer, "Defies The Odds" Photo Credit: Jerod Harris/Getty Images Doctors gave Valerie Harper just three to six months to live after she was diagnosed with terminal brain cancer earlier this year. More than six months later, "The Mary Tyler Moore Show" star, 74, has already surpassed medical expectations and it's possible more good news is coming. Read: Valerie Harper Diagnosed with Terminal Brain Cancer Based on recent tests and scans, the cancer may be retreating for now, People magazine reports. "I'd say that we're getting pretty close to a remission," neuro-oncologist Dr. Jeremy Rudnick, Harper's physician, told "Today" in a taped segment aired on Thursday. "It defies the odds." The doctor continues to tell Harper and her husband Tony Cacciotti that the cancer is not cured and can still "develop resistance to the therapy," but that she now has more time. Related: Valerie Harper "Living Normally" After Terminal Cancer Diagnosis "The problem is, at any time, this can change ... It's not a matter of if (the cancer becomes resistant)," Rudnick told "Today," "it's a matter of when." But Harper is optimistic and ecstatic that by "buying time," she could potentially have one more holiday season with her family. "We're looking at Christmas!" she said.