title: Acromegaly and colorectal cancer: a comprehensive review of epidemiology, biological mechanisms, and clinical implications.
abstract: Acromegaly is an endocrine disorder characterised by sustained hypersecretion of growth hormone (GH) with concomitant elevation of insulin-like growth factor (IGF)-I, and is associated with malignancy and premature mortality from cardiovascular and respiratory diseases. In particular, there may be an increased risk of colorectal neoplasia, but the exact extent of this is contentious. Colonoscopy-based studies of adenoma prevalence rates in acromegalic patients are misleading, but population-based studies on colorectal cancer risk are more consistent - a meta-analysis estimated a pooled risk ratio of 2.04 (95 % CI: 1.32, 3.14). Possible mechanisms underlying this increased risk include direct actions as a consequence of elevated levels of circulating GH and IGF-I and/or other perturbations within the IGF system. Other possible mechanisms include altered bile acid secretion, altered cellular immunity, hyperinsulinaemia, shared genetic susceptibility and increased bowel length. However, most explanations only offer indirect evidence, and the expectation of acromegaly as a natural model of colorectal carcinogenesis has not materialised. From a clinical perspective, it seems reasonable to consider a once-only colonoscopic screening at approximately age 55 years, but potential risks and benefits should be balanced.
authors.affiliation: Department of Surgery, Christie Hospital NHS Trust, Manchester, UK. arenehan@picr.man.ac.uk
authors.forename: A G
authors.initials: AG
authors.lastname: Renehan
authors.forename: J
authors.initials: J
authors.lastname: O'Connell
authors.forename: D
authors.initials: D
authors.lastname: O'Halloran
authors.forename: F
authors.initials: F
authors.lastname: Shanahan
authors.forename: C S
authors.initials: CS
authors.lastname: Potten
authors.forename: S T
authors.initials: ST
authors.lastname: O'Dwyer
authors.forename: S M
authors.initials: SM
authors.lastname: Shalet
mesh_terms: D000172:Acromegaly / Q000150:complications*; D000236:Adenoma / Q000453:epidemiology / Q000473:pathology; D000818:Animals; D003110:Colonic Neoplasms / Q000453:epidemiology / Q000517:prevention & control; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000453:epidemiology*; D006801:Humans; D006965:Hyperplasia; D015994:Incidence; D008954:Models, Biological; D012004:Rectal Neoplasms / Q000453:epidemiology