(CBSNEWS) – Sen. John McCain’s daughter Meghan tweeted an update on her father’s battle with brain cancer as the two enjoyed a hike while in Arizona on Saturday.

“Amazing hike with Dad this morning. Thank you all for your best wishes!” tweeted McCain, along with a photo of the two dressed in hiking gear, overlooking a lush landscape with a furry friend.

McCain stunned the political world last week when he was diagnosed with brain cancer while recovering from surgery to remove a blood clot above his eye. The next step in treatment is likely chemotherapy and radiation, the senator’s doctor said.