McCain hit by cancer claim

John McCain's health has re-emerged as an election issue, as the presidential race enters its last lap with the Arizona senator trailing by large margins in the polls.

John Alan, a cancer specialist based in Massachusetts, has run McCain's medical history through a model that predicts life expectancy after cancer, and found that the Republican presidential candidate has a 12 per cent risk of death over the next two years.

The 72-year-old McCain has had melanomas, virulent manifestations of skin cancer, four times in the past, most recently in 2000 when he had a growth removed from his neck that left him a large scar.

The prognosis will trouble voters who favour McCain over his Democratic rival Barack Obama but who are concerned that a vote for him will ultimately leave his Vice President, Sarah Palin, in the White House.

Meanwhile it has emerged that this year's presidential race is on course to be the most costly ever, with more than $2bn being spent over the cycle of the whole campaign.

A further $3bn has been spent on Senate and House races as the Democrats seek to 'take over' Washington by winning working majorities in both chambers of the Capitol and with Barack Obama taking the White House.