Arizona Senator John McCain has been diagnosed with brain cancer, his office said Wednesday.

Medical officials at Phoenix’s Mayo Clinic Hospital on Friday found a brain tumor known as glioblastoma while the longtime Republican politician was having a blood clot removed from his left eye.

“The Senator and his family are reviewing further treatment options with his Mayo Clinic care team,” McCain’s office said in a statement. “Treatment options may include a combination of chemotherapy and radiation.”

The Senator’s doctors said that he is recuperating from his initial surgery “amazingly well” and that his “underlying health” is excellent.

“Senator McCain appreciates the outpouring of support he has received over the last few days,” his office said. “He is in good spirits as he continues to recover at home with his family in Arizona.”

It’s not clear when McCain will be able to return to his duties in Washington. A vote on the Republican health care bill was delayed last week due to his absence.

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Write to Mathew Katz at matt.katz@time.com.