Republican presidential front-runner Rudy Giuliani said Monday that his health is excellent despite battling prostate cancer in 2000.
"I'm doing great," the former New York City mayor said in an interview on CNBC's "Kudlow & Company." "My PSA is low, nonexistent. I'm cancer-free, I have been for six years. I'm extremely healthy and energetic."
PSA, or prostate specific antigen, is a marker used to track prostate cancer growth. Giuliani dropped out of a campaign for the U.S. Senate after being diagnosed with prostate cancer in April 2000.
Giuliani, who will be 63 in May, leads a crowded GOP field of 2008 candidates in national polls. He said the demanding schedule of a presidential candidate hasn't slowed him down.
"I just got back on a red eye from California and I do four or five speeches, fundraisers, meetings a day - sometimes six," Giuliani said. "So, I've got tremendous energy."
Giuliani also acknowledged the presidential campaign is likely to be his last opportunity for elective office.
"But for me to campaign, this is the year I have to do it," Giuliani said. "And back in 2000, I realized that (I would) have to be a part-time or a quarter-time candidate and that just would have been ... unfair."