Washington (CNN) Sen. John McCain has decided to stop treatment for the brain cancer he has been battling for over a year, his family said Friday in an announcement that precipitated a rare moment of bipartisan empathy in honor of the Vietnam war hero and Republican political veteran.

Colleagues of McCain, 81, had been bracing for the worst for months as the Arizona senator retreated from public life to fight the disease. But Friday's news left them shaken nonetheless. It effectively closes a tumultuous Washington career that included two unsuccessful presidential runs and saw McCain emerge as a singular political figure, an icon of the Senate and latterly as a vehement critic of President Donald Trump.

"Last summer, Senator John McCain shared with Americans the news our family already knew: he had been diagnosed with an aggressive glioblastoma, and the prognosis was serious. In the year since, John has surpassed expectations for his survival. But the progress of disease and the inexorable advance of age render their verdict. With his usual strength of will, he has now chosen to discontinue medical treatment," the McCain family said in a statement.

The statement went on to say: "Our family is immensely grateful for the support and kindness of all his caregivers over the last year, and for the continuing outpouring of concern and affection from John's many friends and associates, and the many thousands of people who are keeping him in their prayers. God bless and thank you all."

Cindy McCain, the senator's wife, wrote in a tweet, "I love my husband with all of my heart. God bless everyone who has cared for my husband along this journey." The senator's daughter, Meghan McCain, said in a tweet, "My family is deeply appreciative of all the love and generosity you have shown us during this past year. Thank you for all your continued support and prayers. We could not have made it this far without you - you've given us strength to carry on."

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