A year and a half after being diagnosed with terminal brain cancer, Valerie Harper tells People she is contining to defy the odds.

"It is looking better and better each test, but it's incurable," the actress, 74, said this week at the Fred and Adele Astaire Awards in New York. "I'm fine. People are wondering … Not fine, but it's not progressing."

The former Rhoda and Mary Tyler Moore Show star said she she chooses to keep a positive outlook despite her diagnosis.

"I don't wake up saying, 'Oh, I'm going to die.' It's a waste of time. It really is," she said.

When Harper was first diagnosed, she was told she had three months to live; that was 18 months ago.

She goes for routine tests every eight weeks.