By JOE WILLIAMS and JOHN M. DONNELLYUpdated 10:10 p.m. | Sen. John McCain will return to the Senate 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 glioblastoma, an often fatal form of brain cancer.

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

Senators said Monday night they still did not know which version they would be debating.

The return of McCain, whose vote is expected to help Republicans clear the procedural hurdle, increases McConnell’s odds for success.