ford announced at a press conference on thursday that he will undergo a 8-10 hour surgery to remove a tumor on may 11 .
he was diagnosed with malignant liposarcoma - a rare type of soft tissue cancer that begins in fat cells or fatty tissue - last year .
he had refused to step down as mayor in light of his crack and alcohol binges , but the diagnosis forced him to give up the role .
but he ran for his old seat in city council and won .