John McCain tweets, "I'm feeling well"

Republican Sen. John McCain, who left Washington for Arizona Sunday, tweeted a thank you for public support during his illness and said he's feeling well and looking forward to coming back to work.

McCain had spent several days last week at Walter Reed National Military Medical Center in Bethesda, Maryland recovering from side effects stemming from chemotherapy treatment for brain cancer. He's spending the holidays with his family and will be skipping the final vote on the GOP tax plan, which is currently expected to take place this week. The House takes up the final tax bill Tuesday, and once they've passed it, the Senate will bring it to the floor.  McCain is expected to return to Washington in January.

The doctor treating McCain at Walter Reed, Dr. Mark Gilbert, Chief of Neuro-Oncology at the National Institutes of Health's (NIH) National Cancer Institute, says McCain has responded well to treatment he's undergone for a viral infection, and his underlying cancer is "responding positively to ongoing treatment."  

While he's in Arizona, McCain will also undergo physical therapy and rehabilitation at the Mayo Clinic.