Sen. John McCain (R-AZ) holds a news conference with fellow GOP senators to say they would not support a 'Skinny Repeal' of Obamacare on July 27. | Chip Somodevilla/Getty Images McCain to return to Arizona for chemotherapy and radiation

Fresh off of casting one of the decisive votes to sink his party’s latest effort to repeal Obamacare, Sen. John McCain (R-Ariz.) will return to his home state to undergo treatment for brain cancer.

“In accordance with the guidance of his physicians, Sen. McCain is returning to Arizona to undergo further treatment at Mayo Clinic,” his office said in a statement Friday. “On Monday, July 31, he will begin a standard post-surgical regimen of targeted radiation and chemotherapy.”


McCain will maintain a work schedule during that time, his office said, with plans to return to Washington at the end of the August recess.

The Arizona senator was diagnosed earlier this month with a particularly aggressive type of brain tumor that was discovered during a surgical procedure to remove a blood clot from behind his eye. The tumor is the same type that killed former Sen. Ted Kennedy (D-Mass.) and Beau Biden, the son of former Vice President Joe Biden.

McCain’s return to the Capitol was at first hailed by Republicans, eager to bolster their narrow Senate majority as they sought to find 50 votes for some sort of repeal-and-replace legislation.

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But McCain flashed his famous independent streak throughout the week, bashing the process by which Republicans advanced their health bill. In a vote early Friday morning, he helped defeat the GOP’s “skinny repeal” measure and dealt a major blow to the party's seven-year effort to dismantle Obamacare.