Dr Tan studied medicine at the University of Melbourne and trained as a plastic and reconstructive surgeon in New Zealand. Following craniofacial fellowships at Oxford and Boston, he was appointed Consultant Plastic & Cranio-Maxillofacial Surgeon at Hutt Hospital in 1995, where was the Director of Plastic Surgery 2000-2006 and Director of Surgery 2007-2013.
He founded the Centre for the Study & Treatment of Vascular Birthmarks, a supra-regional referral centre, in 1996. He was awarded a PhD by the University of Otago in 2001 for his work in infantile haemangioma. He was the Founder and Executive Director of the Gillies McIndoe Research Institute 2009-2023, and Chair since 2024. He was the past President of the Australian and New Zealand head and Neck Cancer Society, and the Founder and Chair of the Head and Neck Cancer Foundation Aotearoa.
He has authored over 230 book chapters and peer-reviewed journal articles on his research in vascular anomalies and cancer, and a recipient of 45 science prizes, honours and awards including Wellingtonian of the Year – Science and Technology, KEA World Class New Zealand Award, and ONZM.