Story highlights Doug Ford says he's honoring his brother Rob's request to run for mayor

Rob Ford withdraws from mayoral race after tumor is found

It's not known if the tumor is malignant or how it will be treated

The mayor has been dogged by his substance abuse

Toronto Mayor Rob Ford, hospitalized this week after the discovery of an abdominal tumor , has decided not to seek re-election.

At the advice of his doctors and family, Ford said he will focus on getting better.

"My heart is heavy when I tell you that I'm unable to continue my campaign for re-election as your mayor," the controversial politician said in a statement Friday. Ford's term officially ends December 1.

"People know me as a guy who faces things head on and never gives up, and as your mayor I have done just that," Ford said. "Now I could be facing a battle of my lifetime, and I want the people of Toronto to know that I intend to face this challenge head on, and win."

Ford asked his brother, Doug Ford, to run for mayor in the October 27 balloting.

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"He told me that he needed me to take the torch while he focuses on getting better," Doug Ford said at a press conference Friday evening outside his mother's home. "He told me he couldn't bear the thought of city hall returning to the old days at the expense of the good, honest, everyday people," he said.

Doug Ford, who has been one of the mayor's strongest supporters during the controversies that have plagued him, said he is honoring his brother's request and would have more details next week about his own campaign for mayor.

The president of Humber River Hospital said Wednesday that the mayor -- just over two months removed from treatment for substance abuse -- has been admitted to the hospital, where doctors will try to get "a definitive diagnosis."

"It is being investigated further and we need to determine exactly what type of tumor it is, and then we can decide on what type of treatment is required," said Dr. Rueben Devlin, the Toronto hospital's president.

According to Devlin, Ford has been "complaining of abdominal pains" for over three months that got worse over the last 24 hours. That prompted the mayor to go the hospital, where a CT scan revealed the tumor in his abdomen.

It's not known yet if the tumor is malignant, according to Devlin.

The health ailment adds to the list of struggles facing Ford, whose fall from grace began in May 2013 with the release of a cell phone video that appeared to show him smoking crack cocaine. The Toronto city council largely stripped him of his mayoral powers months later over those and other allegations of bad behavior.

Ford didn't back down, though, instead vowing "outright war" on the city council.

The mayor apologized for "a lot of stupid things," including having used crack cocaine, but he refused to resign or enter rehab. In fact, despite all the criticism and his becoming a punchline for jokes in Canada as well as the United States, Ford launched a bid for re-election.

This past spring, after a local newspaper reported on a new video that allegedly shows him smoking crack cocaine, Ford relented on one front: by going into rehab.

He returned to work in late June, after a two-month rehab stint, saying he was "ashamed, embarrassed and humiliated" by some of his past actions.

But he refused to resign or refrain from campaigning, saying to the voters of Toronto, "I look forward to serving you for many, many more years."