D. James B. St. John, <scp>AO</scp> , gastroenterologist, mentor and visionary

Professor D. James B. St. John, AO (‘Jim’) passed away peacefully on August 25, 2025, at age 89, leaving a profound legacy in gastroenterology and colorectal cancer prevention. A Melbourne University graduate, Jim trained at leading hospitals in Melbourne and London before returning to Australia in 1967, first to the Monash University Department of Medicine at Alfred Hospital, after which he became the first full-time Director of Gastroenterology at the Royal Melbourne Hospital and Professor at the University of Melbourne in 1977. There, he led clinical and academic efforts for nearly three decades until ‘retirement’. Although he retired from patient care in 2001, he became Senior Clinical Consultant in the National Cancer Control Initiative (2001–2006), Honorary Senior Associate at Cancer Council Victoria and Honorary Clinical Professorial Fellow at the University of Melbourne. His family commented that full retirement never seemed to eventuate. Jim's career commenced with pioneering research into gastrointestinal bleeding and colorectal cancer screening. His early studies with Finlay Macrae and Graeme Young on aspirin-induced bleeding and haemoglobin degradation in the gut laid the groundwork for innovations in faecal occult blood testing. Some years later, after coming across the faecal immunochemical test (FIT), he recognised the rationale for using the more sensitive and specific FIT test for human haemoglobin in stool rather than the older guaiac test. Indeed, he participated in the research in which he and colleagues swallowed their own blood to test the specificity of this approach for the selective detection of bleeding from the large bowel, rather than the stomach. This exemplified his scientific rigour and curiosity. Jim's passionate advocacy for population-based organised colorectal cancer screening began in the late 1970s, leading to the 1991 publication of Australia's screening guidelines through the Australian Gastroenterology Institute, even before the definitive value of the guaiac occult blood tests was proven by randomised controlled trials. He subsequently updated this as an National Health and Medical Research Council Act Guideline for the management of colorectal cancer. His passion was shared globally by early pioneers, including Sidney Winawer, Jack Hardcastle, Jean Faivre, Jack Mandel and Ole Kronborg, who worked together effectively to raise awareness and build the randomised controlled trial-based evidence necessary to ensure that colorectal cancer screening entered mainstream practice and public health policy. Nationally, Jim's and and his colleagues’ clinical research into the application of FIT technology plus persuasive advocacy was instrumental in establishing Australia's National Bowel Cancer Screening Programme, one of the first countries to use FIT in organised screening. That programme has already saved many lives and is projected to save tens of thousands more. As a result, his honours included Officer of the Order of Australia and being the inaugural inductee into the Royal Melbourne Hospital Research Hall of Fame. Internationally, he was one of a group of a dozen world leaders who founded in 1998 the Colorectal Cancer Screening Committee of the now World Endoscopy Organisation, the international network that has ensured that colorectal cancer screening has become effectively embedded in many health care systems. Jim was one of the first to recognise the importance of a family history of colorectal cancer as a risk factor. His documentation of the incidence of bowel cancer in the relatives of the patients of Sir Edward ‘Bill’ Hughes at Monash University is still widely quoted and contributed to the identification of the genes we now recognise as the cause of Lynch syndrome and other familial colorectal cancers. He maintained personal and committed connections with many of these families to the end and ensured the success of the Familial Cancer service at the Royal Melbourne Hospital. Jim has mentored countless clinicians and researchers, inspiring careers through his gentle guidance, careful consideration of the options and visionary thinking. Beyond his achievements, honours and many publications, he is remembered for his integrity, wit, discipline, humility and impeccability. His legacy will endure because he was a respected mentor, colleague and friend to many who followed in his footsteps and whose careers were shaped by him. Jim is survived by his wife Margaret, four children, 12 grandchildren and two step-grandchildren. Vale, Jim.