Neoplastic transformation of sporadic gastric hyperplastic polyps: a systematic review and meta‐analysis of risk factors and clinicopathological features

This systematic review with meta-analysis aims to analyse the existing literature on clinicopathological features of sporadic gastric hyperplastic polyps (GHP), with special emphasis on risk factors associated with neoplastic transformation, as well as available immunohistochemical and molecular data relevant to GHP carcinogenesis. We searched two electronic databases and included studies reporting the presence of dysplasia and adenocarcinoma arising in GHP. Meta-analysis of odds ratios (ORs) was performed using random-effects models. We included 58 studies, 11 of which were included in quantitative synthesis. The overall rate of neoplastic transformation in GHP was 6.0% and progression to adenocarcinoma was observed in 1.5%. Statistically significant risk factors for neoplastic transformation were age ≥65 years (OR 2.60; 95% confidence interval [CI] [1.88-3.59]), size ≥20 mm (OR 4.63; 95% CI [1.82; 11.77]) with increasing size thresholds, as well as intestinal metaplasia (OR 3.65; 95% CI [1.68; 7.97]). Although the evidence is limited, the available data suggest that GHP located in the cardia or arising in a dysplastic background gastric mucosa may represent higher-risk subsets. Immunohistochemical subtyping of dysplasia showed a progressive shift from a predominantly gastric phenotype in non-neoplastic GHP to a hybrid (gastric-intestinal) phenotype in dysplasia and adenocarcinoma. TP53 alterations and chromosomal instability were the most frequently reported molecular events. GHP present a significant neoplastic potential, particularly in the presence of additional clinicopathological risk factors. Lesion size, patient age and - above all - the status of the surrounding gastric mucosa should guide endoscopic management, pathological interpretation and surveillance strategies.