An upbeat Ald. Robert Fioretti, 2nd, announced Tuesday he has cancer and will not run for mayor of Chicago, but will be running for re-election in his ward.

“I’m not afraid of the fight, and although I couldn’t expect this one, I’m going to give it all I’ve got,” Fioretti said.

Fioretti, 57, is a first-term alderman who has differed with Mayor Richard Daley on budget issues. He was the only alderman still expected to get into the race for mayor, at least until Sheriff Tom Dart’s surprise announcement last week that he would not run.

Because he was expected to run for mayor and not alderman, Fioretti could find himself facing competition in a re-election effort for his booming 2nd Ward, which includes part of the Loop and areas on the Near Southwest and Northwest Sides.

Fioretti said he does not know who he will support in the mayoral elections, but that he has been contacted by four candidates in the past few days, some of whom have asked to meet with him.

“I will be sitting down in the next couple of weeks with some of the candidates once they qualify or once they submit their petitions to be on the ballot,” Fioretti said.

Dr. Steven DeAngeles, Fioretti’s doctor, said that the alderman has stage III cancer of the tonsils but that the prognosis for his recovery is good.

The form of cancer is fairly rare, DeAngeles said, and may have been caused by genetic predisposition or environmental factors.

Fioretti said that despite his illness, he had no doubts about his abilities to serve.

“I wouldn’t run for re-election if there was any question in my mind that I could not serve the people of the 2nd Ward or the people of the City of Chicago 100 percent,” Fioretti said to reporters outside his office at City Hall.

Fioretti said he underwent surgery to remove his tonsils on Oct. 20 and will undergo seven weeks of radiation and three sessions of chemotherapy at Northwestern Memorial Hospital starting later this month.

During the surgery, they found cancer in one tonsil and two lymph nodes, all of which was removed, he told the Tribune. “I feel fine,” he said. “The good news is my doctor says I have a great prognosis.”

He said he will continue to campaign throughout his treatment and is not running for mayor because the treatments will take two hours out of his schedule each day. “Running for mayor is a lot different that running for alderman in a ward that I basically consider my backyard,” he said.