Making sense of differing bowel cancer screening guidelines

How can we ensure colonoscopy services are available to those who need them most? owel (colorectal) cancer is the most common cancer affecting both men and women in Australia, with 13 076 cases diagnosed and 4164 deaths reported in 2005. 1 It is the second commonest cause of cancer-related death, behind lung cancer. The incidence of bowel cancer increases exponentially after 50 years of age, with a lifetime risk of about one in 17 among men and one in 26 among women. 1 Bowel cancer satisfies most of the World Health Organization criteria for population cancer screening. 2 Specifically, it is a common, serious cancer, and its natural history is reasonably well understood. It arises from precursor adenomas, and removal of these prevents cancer development. Importantly, most adenomas and early cancers are asymptomatic. Detection at early stages confers an excellent prognosis, and there are numerous tests for early detection and intervention, with the potential to reduce the incidence, morbidity and mortality of the disease. Cancer screening aims to identify affected individuals who do not suspect they have the disease. This is in contrast to performing diagnostic investigations for symptomatic patients, or targeting individuals with a significant family history of bowel cancer, a history of inflammatory bowel disease, previous adenomatous polyps or previous bowel cancer. However, bowel cancer screening recommendations can be confusing for medical practitioners. Numerous tests of varying performance levels are available, and it is difficult to separate recommendations for the population from those targeted towards individuals. There are also significant differences between the Australian recommendations endorsed by the National Health and Medical Research Council (NHMRC) 3 and two recently published American guidelines, from the United States Preventive Services Task Force (USPSTF) 4 and from a collaboration of the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer (representing the American Gastroenterological Association , American Society for Gastrointestinal Endoscopy, American College of Gastroenterology and American College of Physicians) and the American College of Radiology. 5 Interestingly, these guidelines differ due to differing interpretations of essentially the same evidence. It is important to note that the newer American guidelines are less relevant to the Australian health care environment, and should not usurp the existing NHMRC recommendations in Australia. The NHMRC guidelines strongly recommend screening from the age of 50 years, by performing a faecal occult blood test (FOBT) at least every second year. The strength of this recommendation …