NEW YORK -- Mayor Rudy Giuliani, speaking at a hospital news conference hours after undergoing prostate cancer treatment Friday, he went through the procedure with "remarkably little pain."

Doctors implanted radioactive seeds in Giuliani's prostate and said the mayor is "doing great."

Giuliani, dressed casually in a sport jacket and open-collar shirt, had this advice for people: "Don't be afraid of cancer. It's curable, it's treatable, and it can be dealt with."

Doctors at Mount Sinai Hospital used tiny needles to implant radioactive titanium metal pellets, each the size of a grain of rice, into the mayor's prostate gland.

"There were absolutely no complications at all," said Dr. Richard Stock.

"The mayor has done extremely well and is doing very well," Stock said. "The procedure went perfectly."

Giuliani, 56, who has served two terms as mayor, was the favorite to capture the Republican nomination and challenge first lady Hillary Rodham Clinton for a U.S. Senate seat until he announced in April that he had prostate cancer. He officially dropped out of the Senate race a few weeks later.

At the time, Giuliani said he wanted to "put my health first."

Giuliani was expected to be released from the hospital later Friday and to return to Gracie Mansion, the mayoral residence.

"Right now, I feel great," Giuliani said. "I feel like I could go back to work or do whatever I had to do, but I think it's better if I take 24 hours and see if I feel the same way tomorrow."

The mayor said he expected to be back at work on Monday or Tuesday.

Dr. Alexander Kirschenbaum, the mayor's urological oncologist who assisted with the seed implants, said Giuliani was unlikely to cut back on his mayoral duties.

"We can recommend to him, but I'm pretty sure he won't listen to us," Kirschenbaum said. "I'm sure he'll be back working 18 hours a day."

Friday's operation was the second phase of a three-part therapy, Stock said.

In the first phase, Giuliani had been taking hormones to limit the growth of cancerous cells by controlling the production of male sex hormones, including testosterone.

"The next phase of the treatment will take place two months after the implant," Stock said, "and will involve external-beam radiation therapy that will be daily treatments Monday through Friday for a five-week period." The mayor also will continue to take hormones for three more months.

"His prognosis is excellent," said Kirschenbaum. "I expect him to be cured. He's doing great."

When the mayor announced he would not be seeking the Senate seat, he said he needed time to focus his efforts on fighting the cancer and to figure out the best treatment.

His reported choices were surgery to remove the prostate, external beam radiation and radioactive seed implantation.

With the seed implantation, doctors guided by ultrasound imaging use long, hollow needles to insert the seeds into the prostate. The American Cancer Society says five-year survival rates following the therapy exceed 90 percent.

In briefing reporters at City Hall on Friday morning, Deputy Mayor Joseph Lhota said of Giuliani: "He told me to tell you that when you see him next he will be radioactive, and he looks forward to somehow or another interfering with your transmissions on television."

The Associated Press and Reuters contributed to this report.