WASHINGTON — Sen. John McCain will return to the chamber Tuesday in time for a key procedural vote on the Republican legislation to repeal and replace the 2010 health care law, his office confirmed Monday evening.

The Arizona Republican announced last week he was diagnosed with brain cancer.

The news is a boost to the Republican effort to overhaul the U.S. insurance system. Senate Majority Leader Mitch McConnell needs the support of at least 50 of the 52 Republican members to vote to clear the motion to proceed to the House-passed repeal and replace bill in order to bring up a Senate version for consideration.

The return of McCain, who is expected to cast a vote that would help Republicans clear the procedural hurdle, increases McConnell’s odds for success.

It is unclear whether several swing votes, like Sens. Lisa Murkowski of Alaska, Dean Heller of Nevada and Shelley Moore Capito of West Virginia, will support the motion to proceed.

“Sen. McCain looks forward to returning to the United States Senate tomorrow to continue working on important legislation, including health care reform, the National Defense Authorization Act, and new sanctions on Russia, Iran and North Korea,” McCain’s office said in a statement.