O'Morain, C.

pylori cancer study patient helicobacter eradication gastriti metaplasia infection h pylori infection helicobacter pylori infection lesion dysplasia recommendation treatment evidence level gastroenterol pepsinogen h pylori h pylori eradication pylori eradication helicobacter pylori grade serum population atrophy diagnosis aliment pharmacol helicobacter pylori eradication endoscopy biopsy follow-up endoscopic group precancerou factor management gastroenterology result condition porto ulcer portugal trial review development progression statement screening carcinoma surveillance therapy system resistance effect society department disease european country premalignant virchow precancerous lesions di mario f classification epithelial dysplasia pathology dinis-ribeiro kuiper testing mucosa cohort choice treatment university pathol assessment /lesion clarithromycin extent