WASHINGTON (CBSNewYork/AP) — Senator John McCain is heading back to work Tuesday ahead of a crucial vote on health care reform.

The announcement comes just days after the senior senator from Arizona received an alarming brain cancer diagnosis.

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“Senator 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 Monday.

Last Wednesday, doctors revealed that McCain has been diagnosed with glioblastoma, an aggressive cancer. GOP senators were meeting about long sought after health care overhaul when they got the devastating news.

The Republican senator underwent a procedure to remove a blood clot from above his left eye less than a week before that.

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“It’s a primary brain tumor,” CBS News’ Chief Medical Correspondent Dr. Jon Lapook said last week. “It’s a very serious brain tumor. It’s the same one that killed Ted Kennedy.”

On Tuesday, the Senate will vote to try opening up debate on a bill to replace Obamacare.

McCain was the GOP’s presidential nominee in 2008, when he and running mate Sarah Palin lost to Barack Obama.

A Navy pilot, McCain was shot down over Vietnam and held as a prisoner for 5 ½ years.

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(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)