The plan by Sen. John McCain's campaign to release his medical records this morning has many wondering just what they will reveal about the 71-year-old war veteran.
Voters may be concerned about how McCain's health will hold up over his term if he is elected in November, given his history of melanoma, as well as the possibility that his age leaves him more prone to dementia.
Will Age Be a Factor?
McCain has been labeled by some as "too old" to run for president. However, aside from moderately high cholesterol, for which he takes medication, doctors say McCain is in exemplary shape for his age.
"The actuarial tables say if you make [it] to 71 in overall good health, your life expectancy is about 16 years. That would be to about to age 87," ABC News medical editor Dr. Tim Johnson told Charles Gibson on "World News."
But, Johnson noted, McCain's continued mental acuity is a much more difficult question to answer especially because increasing age is the single biggest risk factor for developing memory loss and dementia.
Dr. Gary Small of the University of California, Los Angeles, told ABC News that McCain should undergo screening to ensure that he does not have an onset of dementia -- the risk of which is around 20 percent for someone his age.
But some argue that age may, in fact, be an advantage. An article in Tuesday's New York Times documents research showing that, with age, the brain may take in more information to make a wiser decision.
When asked whether McCain's age would give him a mental handicap, Small replied, "Nobody's perfect."
The Cancer Factor
Another concern is McCain's history of skin cancer.
McCain had a melanoma roughly the size of a nickel removed from his left temple in 2000 -- a surgery from which he still bears a prominent scar.
However, given that McCain has had no further skin cancer in the last eight years, most physicians seem to agree that the chances of a fatal melanoma are minimal.
"The fact that he has survived almost eight years is very much in his favor," Johnson told ABC News. "But he needs to be checked very carefully several times a year because he is at higher risk for a new melanoma than someone who has never had one."
"At eight years out with no evidence of recurrence, the probability of recurrence is in the single digits, as is the chance [of] death from recurrence," said Dr. Stuart R. Lessin, director of dermatology at the Fox Chase Cancer Center in Philadelphia.
Some have questioned why McCain received what they would term "aggressive" treatment when his melanoma was removed.
But Dr. Darrell Rigel of the NYU Medical Center said that the treatment is what would have been commonplace in 2000.
"I don't think it was such a major procedure for a major melanoma, especially eight years ago," he said.
"It's on the aggressive end of the spectrum, but it's not like commando," said Rigel, adding that it is how he would treat a patient who told him, "Look, I want to do everything possible to ensure that this is out."
Rigel also noted that the lack of a melanoma recurrence is important for other reasons.
"The fact that he hasn't had one in the last eight years suggests that for the past 20 years he's been protecting himself from the sun," he said.
Rigel also said that melanomas are very common, with 180,000 diagnosed in the United States each year.
But dermatologists don't expect McCain's history of melanoma to affect his campaign.
"If this was 2000 instead of 2008, would it impact it eight years ago? Yeah, because you wouldn't know which pool he'd be in," said Rigel, speaking about the chance that McCain could have been among the 30 percent of survivors who die from a melanoma recurrence.
But now, experts place McCain's chances of a fatal melanoma in the single digits and only slightly higher than someone who has never had one.
"Eight years out … the chance of it coming back is really remote," said Rigel. "The melanoma itself is not going to be the critical thing at this point."
Dan Childs contributed to this report.