BACKGROUND: Wilson's disease is associated with heavy copper overload, primarily in the liver. Copper is a toxic metal, and might be expected to be associated with cancer induction, as iron is in haemochromatosis. However, liver cancer is currently believed to be extremely rare in this disease, and other intra-abdominal malignancies have not been reported. AIM: To assess the frequency of abdominal malignant disease in patients with Wilson's disease on long-term follow-up. DESIGN: Retrospective study in two specialist Wilson's disease clinics: Cambridge/London and Uppsala. METHODS: We reviewed the case records of 363 patients seen at three centres: Addenbrooke's Hospital, Cambridge, 1955-1987; the Middlesex Hospital, London, 1987-2000; and the University Hospital, Uppsala, Sweden, 1966-2002. Patients were grouped by length of follow-up: 10-19 years; 20-29 years; 30-39 years; and 40 years or more. RESULTS: No cancers were seen in patients followed for