The long term outcome of gastric non-invasive neoplasia.

BACKGROUND: The cancer risk associated with gastric non-invasive neoplasia (formerly dysplasia) is debated. This prospective long term follow up study investigates the clinicopathological behaviour of non-invasive gastric neoplasia (and related lesions), focusing on the cancer risk associated with each different histological phenotype. PATIENTS AND METHODS: A total of 118 consecutive cases (nine indefinite for non- invasive neoplasia; 90 low grade non-invasive neoplasia; 16 high grade non- invasive neoplasia; and three suspicious for invasive adenocarcinoma) with a histological follow up of more than 12 months (average 52 months; range 12-206) were prospectively followed up with a standardised protocol. Patients in whom gastric cancer was detected within 12 months from the initial diagnosis of non-invasive neoplasia were excluded, assuming that invasive carcinoma had been missed at the initial endoscopy procedure. RESULTS: Non-invasive neoplasia was no longer detectable in 57/118 cases (48%), was unchanged in 32 (30%), and evolved into gastric cancer in 20 patients (17%). Evolution to invasive adenocarcinoma was documented in both low and high grade non-invasive neoplastic lesions (8/90 low grade; 11/16 high grade) and correlated with histological severity (low versus high grade) at baseline (p<0.001). Seventy five per cent of cancers occurring during the long term follow up were stage I. CONCLUSIONS: The risk of invasive gastric cancer increases with the histological grade of the non-invasive neoplasia. Following up non-invasive gastric neoplasia increases the likelihood of gastric cancer being detected in its early stages.