Rob Ford says he will be 'out of commission' for about four months after he undergoes potentially life-saving cancer surgery on May 11.

Speaking outside Mount Sinai Hospital on Thursday afternoon following an appointment with his doctors, the former mayor of Toronto provided more details about the upcoming operation.

"The good news is they can operate because the tumour has shrunk," he said, adding that one of the tumours did not shrink to the size doctors had hoped.

"They are happy how the treatment went and the tumour in the back they said has pretty well disappeared. So I am very, very happy and delighted."

Ford said four surgeons will be participating in the operation, which will likely take between eight to 10 hours. He said he will also be in the hospital for approximately 10 to 14 days following the surgery.

"This summer I won't be able to do too much. I'm pretty well writing off the summer," he said.

The Ward 2 councillor said he hopes to be able to return to work by September 1.

Ford, who was diagnosed with a rare form of soft tissue cancer in September, thanked his doctors, family and members of the public for their support.

"People, really all over the world, I've been getting best wishes and I can't thank them enough for the heartfelt thanks and appreciation that they have given me. I don't think I could have got through this fight that we are fighting," he said.

"If it wasn't for this hospital, I probably wouldn't be here by now... I'm just lucky to be alive today and I am just lucky that I'm getting another chance at life."

Mayor John Tory issued a statement Thursday, offering well wishes to Ford and his family.

"While Councillor Ford and his family still face some challenging days ahead as he told us today, I have confidence in our health care system, his fighting spirit and the support he has from his family, colleagues and the people of Toronto," Tory said in the written statement. 

"On behalf of all Torontonians, I offer thoughts, prayers and good wishes to Councillor Ford and his family. We are all hoping for the very best and looking forward to him being back at full strength and good health as soon as possible."

Speaking to CP24 during a one-on-one interview Thursday evening, Ford said the diagnosis has forced him to, in part, change his outlook on life.

"Everybody has good and bad days and things happen to us but when you are fighting for your life, you put everything in perspective," he said.

"I just had to keep thinking positive... a lot of the stuff I used to worry about, I don't worry about that anymore."

Remember for instant breaking news follow @cp24 on Twitter.