U.S. Senator and former presidential candidate John McCain diagnosed with brain tumour

John McCain, the 2008 Republican presidential nominee and a former prisoner of war, has been diagnosed with brain cancer.

McCain, 80, underwent surgery last week to remove a blood clot from above his left eye. Tests then revealed that “a primary brain tumour known as a glioblastoma was associated with the blood clot”, according to the Mayo Clinic, whose doctors performed the surgery in Phoenix, Arizona.

Glioblastoma is a particularly aggressive form of brain tumour affecting adults. The American Cancer Society puts the five-year survival rate for patients over 55 at around just 4 per cent.

McCain and his family are now reviewing further treatment options, which could include chemotherapy and radiation.

The news of McCain’s cancer was met with widespread support as figures from across the American political spectrum rallied around a political icon.

President Donald Trump said: “Senator John McCain has always been a fighter. Melania and I send our thoughts and prayers to Senator McCain, Cindy, and their entire family. Get well soon.”

Former President Barack Obama, who beat McCain to the presidency in 2008 after a contentious battle that featured accusations of racism against the Republican, wrote on Twitter that “John McCain is an American hero & one of the bravest fighters I’ve ever known. Cancer doesn’t know what it’s up against. Give it hell, John”.

McCain, now the senator for Arizona, was shot down over Hanoi in 1967 as he conducted a bombing mission during the Vietnam War. He was injured while parachuting out, captured and subsequently tortured during his five years as a prisoner of war.

When McCain criticised Trump’s policies in 2015 during the Republican presidential primaries, the then-candidate mocked his party stalwart. “He’s not a war hero,” said Trump. “He was a war hero because he was captured. I like people who weren’t captured.”

Since then McCain has continued to voice his opposition to some of Trump’s most extreme positions and statements, but has nonetheless been a relatively reliable vote for Republican proposals in Congress.

News of McCain’s illness came as Republicans met late into the night in Washington in a last-ditch, Trump-ordered attempt to thrash out a deal to repeal Obama’s landmark healthcare legislation. McCain’s absence will make the already difficult task of passing a bill through the Senate nigh on impossible for GOP leaders who need every vote they can muster.