Specialisations: 

– High-quality screening colonoscopy and gastroscopy

– Advanced interventional endoscopy: EUS, ERCP, EMR, ESD, enteroscopy, cholangioscopy

Where Dr Keegan practices:

– Northern Beaches: Frenchs Forest, Dee Why, Mona Vale

– North Shore: St Leonards, Wahroonga

Dr Mathew Keegan, MBBS, FRACP, is a Sydney gastroenterologist and advanced interventional endoscopist with subspecialty expertise in pancreaticobiliary and luminal endoscopy. He practices across Sydney’s Northern Beaches and North Shore, providing high-quality screening, diagnostic and surveillance colonoscopy and gastroscopy alongside advanced minimally invasive treatment for complex gastrointestinal, pancreatic and bile duct conditions.

Dr Keegan brings a thorough, compassionate and considered approach to care. He takes time to understand each patient’s symptoms, medical history and individual circumstances, explain findings clearly and discuss the available options. He is persistent in seeking answers, considers the full clinical picture and explores appropriate avenues of investigation when symptoms or findings are complex. His clinical decisions are guided by current evidence, best-practice standards and the most up-to-date national and international guidelines.

At the heart of his approach is a simple principle: to recommend the course of care he believes is most appropriate for the individual patient. This may include further investigation, multidisciplinary discussion or referral to another specialist when additional expertise would benefit the patient.

He has particular expertise in bowel cancer screening, complex polyp detection and removal, Barrett’s oesophagus surveillance, Endoscopic Ultrasound (EUS), ERCP, Endoscopic Mucosal Resection (EMR) and Endoscopic Submucosal Dissection (ESD). EMR and ESD are minimally invasive techniques that allow selected large or complex precancerous lesions and early gastrointestinal cancers to be removed through an endoscope. ESD can enable en bloc removal—in a single piece—supporting precise pathological assessment and, for appropriately selected lesions, potentially providing an organ-preserving alternative to more invasive surgery.

Alongside his clinical practice, Dr Keegan is actively involved in advancing the quality of endoscopy through research, education, quality improvement and professional collaboration. He has a particular interest in early cancer detection, diagnostic accuracy, the appropriate use of technology in endoscopy and refining advanced endoscopic techniques to improve safety and patient outcomes.