Barrett's oesophagus (BO) is intestinal metaplasia replacing the normal squamous epithelium of the distal oesophagus. BO is a premalignant condition with a well-known sequence of histological changes, which can progress to adenocarcinoma through low-grade dysplasia (LGD) and high-grade dysplasia (HGD). When HGD is detected, the risk of malignant transformation is around 16–59% in five years, while the risk of progression to adenocarcinoma is 0.3% per year when there is no dysplasia.1, 2, 3 For that reason, clinical guidelines recommend endoscopic surveillance with biopsies at regular intervals.4, 5 However, it is well known that the degree of compliance with the recommendations is variable and endoscopic biopsies have limited utility.6, 7 More precise methods are therefore needed to identify BO patients at higher risk of malignant progression in order to establish effective prevention measures.

The incidence of oesophageal adenocarcinoma has increased in developed countries in recent years.8, 9 This has been attributed to obesity and metabolic changes deriving from excess weight, regardless of whether or not the patient has gastro-oesophageal reflux disease (GORD), due to there being a molecular mechanism for carcinogenesis associated with obesity which leads to the development of insulin resistance.10, 11, 12 Increased insulin levels promote carcinogenesis by stimulating the production of insulin-like growth factor 1 (IGF-1) and inhibiting the production of IGF-1 binding proteins (IGFBP-1 and IGFBP-3). The net effect is an increase in bioavailable IGF-1, which activates pathways involved in tissue proliferation, as it is a potent stimulator of mitogenesis.13, 14, 15 For example, the association between IGF-1 levels and prostate and colorectal cancer and breast cancer in premenopausal women has already been demonstrated.14, 16

The association of circulating levels of obesity-related biomarkers with the risk of BO and oesophageal adenocarcinoma has been studied previously, but results have been inconclusive and contradictory at times.17, 18, 19, 20, 21 The aim of this study therefore was to measure serological levels of the IGF complex in patients with BO at different histological stages and oesophageal adenocarcinoma and look for any correlation between these biomarkers and histological progression.