Dr Koong and Dr Ho both graduated from the National University of Singapore with Bachelors of Medicine and Bachelors of Surgery. Following their graduation, both worked in Singapore public health institutions for many years. They became surgical trainees while working in the Department of General Surgery, Singapore General Hospital under the leadership of Professor Soo Khee Chee.

In the later years of their training prior to their overseas training, both of them were involved in the start-up of the National Breast Cancer Screening Programme. In those years, they had contributed to the protocol development, monitoring and auditing of the study data.

In 1998, they left for their overseas training at Memorial Sloan Kettering Cancer Centre where Dr Koong started his advanced thoracic surgery training while Dr Ho Gay Hui trained further her breast surgical oncology expertise.

Memorial Sloan Kettering in Manhattan
Both Dr Koong and Dr Ho trained here from 1998 to 2000.

They returned to Singapore in 2000 and joined the National Cancer Centre Singapore as Surgical Consultants under the Department of Surgical Oncology.