Meghan McCain says she's "cautiously optimistic" that Sen. John McCain could return to Washington by the summer.
Meghan McCain told KTAR-FM on Tuesday that her father is doing well as he continues to undergo treatment in Arizona.
The 81-year-old Republican senator has been battling a rare and aggressive form of brain cancer called glioblastoma. He was diagnosed last summer.
John McCain was hospitalized and treated for a viral infection in December. He has remained at his family's ranch near Sedona to undergo chemotherapy and physical therapy since mid-December.
Meghan McCain says her father has been working through the side effects of chemotherapy, but she feels "very lucky that he is doing so well."
The senator had initially expected to return to Washington in January, but was unable to do so.