CHAPEL HILL (AP) -- His wife's cancer has returned, but former North Carolina senator John Edwards says he'll continue his campaign for the Democratic presidential nomination.

Edwards canceled a Tuesday evening house party in Iowa to go with his wife to a doctor's appointment, which his campaign described as a follow-up to a routine test she had on Monday.

John Edwards said a biopsy of her rib had showed that the cancer had returned.

The bone is one of the most common places where breast cancer spreads, and once it does so it is not considered curable.

But how long women survive depends on how widespread the cancer is in the bone, and many can survive for years. The longer it takes for cancer to spread after the initial tumor, the better the prognosis. She was diagnosed in 2004.

However, Edwards isn't forgoing his run at the White House, saying, "The campaign goes on. The campaign goes on strongly."

(Copyright 2007 by The Associated Press. All Rights Reserved.)