He completed his MBBS in 1983 at the National University of Singapore, FRCS (Gen Surg) in 1989 at the Royal College of Physicians and Surgeons of Glasgow, UK and FAMS (Gen Surg) in 1995 at the Academy of Medicine, Singapore.Dr Denis Cheong was a senior consultant in the Department of General Surgery at Tan Tock Seng Hospital. He was responsible for developing Medical and Radiation Oncology and pioneered the development of laparoscopic (keyhole) colorectal surgery. He is multilingual and his works involves screening for colon cancer and polyps, diagnostic and therapeutic gastroscopy and colonoscopy, hernia repair - open/laparoscopic, diverticular disease and inflammatory bowel disease and many others.