(RNN) - The family of Sen. John McCain said Friday that he would not be continuing with his cancer treatment.
His daughter, Meghan McCain, released a statement on Twitter.
"In the year since (his diagnosis), John has surpassed expectations for his survival," the family said. "But the progress of disease and the inexorable advance of age render their verdict."
They said he chose to stop the treatments "with his usual strength of will."
They thanked the caregivers who had supported him and showed kindness, as well as the people who had expressed their support and kept him in their prayers.
"My family is deeply appreciative of all the love and generosity you have shown us during this past year," Meghan McCain said.
The longtime Arizona politician and 2008 Republican presidential nominee was admitted to Walter Reed Medical Center in December after experiencing side effects from his cancer therapy. He had surgery in July 2017 for a blood clot and was diagnosed with glioblastoma, the same brain cancer that claimed the life of former senator Ted Kennedy.
McCain said in September that his doctors told him it was a "very poor prognosis."
"I just said, 'I understand,'" he said during an interview on "60 Minutes." "Now we're going to do what we can, get the best doctors we can find, and do the best we can and at the same time, celebrate with gratitude a life well-lived."
In April, McCain underwent surgery for an infection related to diverticulitis, an intestinal condition. His wife Cindy McCain and daughter Meghan McCain both tweeted that he was in stable condition after the surgery, and was recovering.
The same month, Apple News published an excerpt of McCain's upcoming memoir, "The Restless Wave," in which McCain lamented the current political climate of hyperpartisanship and emphasized the importance of compromise in governance. He also wrote that he was serving out his last term in the Senate.
"This is my last term. If I hadn't admitted that to myself before this summer, a stage 4 cancer diagnosis acts as ungentle persuasion," McCain wrote.
McCain had in recent weeks held conference calls with his staff from his Arizona home, where old friends and colleagues, including former Vice President Joe Biden, visited to check up on McCain and provide support.
In December, Biden consoled Meghan McCain as she tearfully spoke of her father's illness on ABC's "The View." Biden's son Beau died in 2015 after fighting glioblastoma. Biden held Meghan McCain's hand, telling her not to lose hope because medical breakthroughs are possible and that if anyone could beat brain cancer, it would be her father.
McCain, considered a maverick by some, lashed out at President Donald Trump in March of 2018, after the president congratulated Vladimir Putin on his re-election.
In 2014, McCain issued repeated warnings about a resurgent Russia under President Vladimir Putin after the Russian takeover of Crimea. As a leader of the Armed Services and Foreign Relations committees, he led a group of senators that saw Putin's Russia as America's greatest threat on the world stage.
A Vietnam POW and a known defense hawk, McCain lost his bid for the White House to Barack Obama. McCain was the first GOP nominee to select a woman to be a vice-presidential nominee, Alaska Gov. Sarah Palin.
The ticket failed to gain lasting traction in the face of an inspiring Obama campaign, especially following a financial crash in the fall of 2008 while George W. Bush was president.
McCain has often been at odds with his own party. During a vote that would repeal the Affordable Care Act, also known as Obamacare, McCain walked to the front of the chamber and voted against repeal by giving it a thumbs down. The moved shocked his fellow Republicans, who thought the repeal of the law was a done deal.
McCain lent his name to the Bipartisan Campaign Reform Act, commonly referred to as the McCain-Feingold Act, which amended the Federal Election Campaign Act of 1974. The law was passed in 2002 and regulated "soft money" donations to campaigns, as well as advertisements that advocated for an issue.
However, in 2008 the Supreme Court overturned a section of the act, which increased the limit on campaign contributions of a candidate who was opposing someone using their personal wealth to finance their campaign.
Then in 2010, the high court struck down sections of the law that limited how much corporations and unions could donate, citing the First Amendment.
As a Navy pilot in the Vietnam war, McCain was shot down over Hanoi in October of 1967 while on his 23rd bombing mission inside a Skyhawk dive bomber. He ejected from the plane, which knocked him unconscious and broke both his arms and a leg. He landed in a lake in the corner of the capital of North Vietnam, he said in recalling the incident.
McCain was taken prisoner and stayed in the infamous Hanoi Hilton while in captivity for more than five years.
He was given bad medical treatment by the North Vietnamese, which left McCain with lifelong injuries. He spent two years in solitary confinement and later gave a riveting account of his time in North Vietnam.
He was released in March of 1974 along with others from a POW camp. After Vietnam, he served in the nation's capital as a naval liaison to the U.S. Senate, a body in which he would later become a fixture.
McCain was born on Aug. 29, 1936, at a naval station in the Panama Canal Zone to naval officer John S. McCain Jr., and Roberta. He graduated from a prep school in Alexandria, VA, in 1954.
The son and grandson of Navy admirals, McCain entered the Naval Academy in 1954 and served until 1981.
He was elected to the U.S. House of Representatives from Arizona in 1982 and was elected to the U.S. Senate in 1986.
McCain mounted two runs for the presidency, losing the GOP nomination to George W. Bush in 2000, but capturing the party's nomination eight years later.
McCain's naval honors include the Sliver Star, Bronze Star, Purple Heart, Legion of Merit and Distinguished Flying Cross.