Updated 5:30 p.m. | Posted 12:22 p.m.
Addressing his health in detail after collapsing Monday night during his State of the State speech, Gov. Mark Dayton told reporters Tuesday that he has prostate cancer but remains up to doing the job and plans to finish his term, which ends in a little less than two years.
The fainting spell Monday night "was situational and related to standing for a long time while giving his speech and possible dehydration. It is not related to his prostate cancer diagnosis," said Mayo Clinic spokesperson Karl Oestreich.
Dayton said his Tuesday afternoon appointment at Mayo was aimed at giving Minnesotans assurance that he's fine after his collapse. The governor said he has a separate cancer-related appointment next week.
• Mayo Clinic: What is prostate cancer?
Dayton, 69, had paused during his speech to take a drink of water. He seemed to waver a bit, and then collapsed, apparently hitting his head before falling to the floor. Officials said he recovered quickly and acting normally within 20 minutes of the collapse and poking fun at himself.
"If I had known it would result in Republicans not criticizing my speech I would have tried it years ago," the governor joked Tuesday, adding that he was grateful for the outpouring of help and sympathy from both sides of the aisle.
A biopsy last week confirmed the cancer.
"Obviously it was a grim diagnosis," Dayton said but added that the cancer had not spread.
Dayton insisted he had the stamina to carry him through two more years. He said he won't step down but added that his health is a legitimate public issue and he'd be as forthcoming as possible about his medical condition.
The severity of the cancer will dictate what, if any, treatment is recommended and Dayton and his doctors might decide to do nothing for now, said Badrinath Konety, chair of the University of Minnesota Urology Department.
"If he had a low-risk prostate cancer or even a small amount of medium-risk prostate cancer, I would probably be inclined to watching this for awhile, at least until he is done with his term and has the ability to focus on treatment more," said Konety, who is not involved in the governor's care.
"That would not pose any kind threat to his life in that interim time period and he should have no deletorious side effects of just watching it," he said.
A higher-risk assessment could make surgery, radiation or a newer therapy unavoidable. Those could slow him down or force him to take time off.
Prostate cancer is among the most common cancers for men, and Konety said about 40 percent fall into the low-risk category at the time of diagnosis.
The disease affects a gland near the bladder and rectum. The cancer can make urination painful and is sometimes fatal. But other men who have it don't experience much discomfort and can live for many years after it is treated.
One in seven men will be diagnosed with prostate cancer during his lifetime, according to the American Cancer Society.
Most new cases are in men older than 65 years old. Dayton turns 70 on Thursday.
The governor said his father had prostate cancer surgery when he was about the same age but went on to live for 25 more years.
"They told him five years later that he would die of something but it wouldn't be prostate cancer," he added. "So I hope for the same result."
Dayton said he had planned to make the cancer diagnosis public after deciding on a course of treatment. But after Monday night's fainting spell, in which he hit his head and briefly lost consciousness, made him reveal details sooner.
"I believe they are two separate issues," he said. "I'm not a doctor, but I don't believe there is any connection. I don't feel anything. I wouldn't know I had prostate cancer if it weren't for the tests. I don't feel any effects."
Konety said that prostate cancer rarely interferes with the central nervous system.
Dayton on Tuesday recalled feeling warm in the House chamber prior to Monday night's speech. About 45 minutes into the speech, he said he began feeling like something wasn't right.
"It came up on me before I could do anything about it," the governor added. "The speech was too long. I learned that lesson."