"Rob has always been so strong for all of us and now I ask us all to be strong for him," Coun. Doug Ford said in a statement issued minutes after a doctor announced the mayor's diagnosis.
"I can't begin to share how devastating this has been for Rob and our family. He is an incredible person, husband, father, brother and son and he remains upbeat and determined to fight this."
Dr. Zane Cohen of Mount Sinai Hospital told a packed news conference that Rob Ford had been diagnosed with malignant liposarcoma — a type of cancer that arises from fat cells and can attack a variety of soft tissues in the body. It makes up about one per cent of cancers, he said.
"It has about 60 different cell types and that's what makes it a very rare tumour and a very difficult tumour," Cohen said, refusing to estimate a survival rate for this type of cancer.
He added that the mayor had been given a clean bill of health in 2011, which mean that the tumour — which he described as 12 centimetres by 12 centimetres in size — had developed since then.
"We think it's a fairly aggressive tumour, mainly because these types of tumours are often slow growing. To get to the size that it is now it's often a couple of years ... So it's fairly aggressive."
Nonetheless, the clinical team treating Ford are tackling the tumour aggressively, said Cohen, who explained that Ford will undergo two rounds of chemotherapy treatment over the next 40 days before doctors reassess his condition.
"We are optimistic about treatment. This particular liposarcoma is more sensitive to chemotherapy than most sarcomas, that is an optimistic statement in and of itself," Cohen said.
Following the chemotherapy and its results, doctors may or may not decide to carry out surgery or radiation treatments.
"It will all depend on the response to the initial treatment and subsequent treatment," Cohen said. "It's fairly aggressive, but we are treating this very aggressively in order to eradicate the tumour."
In 2010, 1,175 Canadians were diagnosed with soft-tissue sarcoma; about 470 died of the disease in 2009, according to the Canadian Cancer Society, which cited the most recent years for which statistics are available.
Prime Minister Stephen Harper said the thoughts and prayers of all Canadians were with Ford, who has two young children, and his family at this difficult time.
"We wish him a speedy and complete recovery and are certain that he will take on this fight with all of his characteristic tenacity and energy," Harper said in a statement.
Ford's stunning diagnosis came a week after the mayor went to hospital complaining of "unbearable pain." At the time, doctors told a hastily-called news conference they had found a tumour in his abdomen, although they didn't know if it was cancerous.
It took two biopsies to determine that Ford's tumour was malignant, Cohen said.
The internationally recognized colorectal surgeon said doctors also found a "small nodule" in Ford's buttock, behind the left hip, which is part of the same abdominal tumour they discovered last week.
Cohen said Ford is still in some pain, which is being managed with medication.
Cohen also said that it was "impossible to predict" how the chemotherapy would affect Ford, but said he thought the mayor would be able to handle it.
"He's going to have some tough days but he'll have more good days and bad days," he said.
The 45-year-old mayor, whose tenure has been marred by scandal and admitted substance abuse, withdrew his candidacy for re-election last Friday, opting instead to run as a councillor in next month's election. His older brother joined the mayoral race in his stead.
Cohen said he wasn't in a position to comment on whether Ford ought to be running in the municipal race.
"I can't really advise (what) to do or not to do," he said. "I think it will depend on his response to the initial treatment."
Ford's father, former Ontario politician Doug Ford Sr., died in 2006 of colon cancer three months after he was diagnosed with the disease.
Rob Ford — who has turned into an international celebrity due to a series of scandals touched off by reports of a video appearing to show him smoking crack cocaine — returned to office just over two months ago after a stint in rehab for substance abuse issues.
His role as mayor has been largely symbolic since last November, when he was stripped of most of his powers following his admissions of alcohol abuse and drug use during "drunken stupors.''
Federal, Ontario and Toronto politicians, including the top candidates vying for the mayor's job, rallied around Ford and his family.
"My sincere hope is that Mayor Ford can beat this and my thoughts are with him and his family," Ontario Premier Kathleen Wynne said in a statement.
"I know he's been receiving a great number of good wishes. Those thoughtful words — along with the care of the team at Mount Sinai — are sure to help set him on the road to restored health."
Olivia Chow, whose husband, former NDP leader Jack Layton, died from cancer in 2011, said she had reached out to Ford soon after he was hospitalized last week.
"It's really sad that Rob Ford has this diagnosis but I know he's strong, he's a fighter and I know he can beat these cancer cells," said Chow, who fought her own battle with thyroid cancer years ago.
Martin Kabat, CEO of the Canadian Cancer Society's Ontario Division, said the Ford family can reach out to the society for information and the "support they need to cope with the stress" following the cancer diagnosis.
"We wish Rob Ford a successful treatment and full recovery," Kabat said in a statement.
— With files from Abdul Latheef.