The benefits of endoscopy have increased enormously as it has matured from a purely diagnostic tool to become a therapeutic subspecialty, but so too has the potential for causing harm. Endoscopic haemostasis for varices and ulcers, relief of biliary obstruction from stones or tumours, and alleviation of luminal obstruction using balloons, bougies and stents improve quality of life and may obviate the need for operative surgery, but all risk serious complications. The risks of endoscopy are worth taking only when the procedure is worth doing and when the benefits outweigh the risks. Complications are unacceptable if endoscopy is not indicated; pancreatitis after diagnostic endoscopic retrograde cholangiopancreatography (ERCP) and colonoscopic perforation done during follow-up of a single rectosigmoid polyp are examples. The risk:benefit ratio is dictated by the disease process and by the underlying health of the patient—thus (to rehearse an old chestnut), the complications of endoscopic bile duct clearance are probably fewer and better tolerated than those of surgical exploration in the elderly and frail and are therefore acceptable; the same may not be true for younger and fitter patients for whom surgery has a lower complication rate than ERCP. Relatively high-risk endoscopic procedures can be justified to palliate symptoms in patients with terminal diseases, whereas the risks become unacceptable when the same procedure is done to a patient with surgically respectable disease.

These issues received considerable airing in the National Confidential Enquiry into Patient …