Gastrointestinal NeoplasmsUpper Gastrointestinal TractStomach NeoplasmsEsophageal NeoplasmsGastrointestinal TractPancreatic NeoplasmsDigestive SystemAdenocarcinomaGastrointestinal DiseasesColorectal NeoplasmsEndoscopy, GastrointestinalGastrointestinal HemorrhageFluorouracilEsophageal DiseasesDuodenitisCausticsStomachColonic NeoplasmsLiver NeoplasmsEndoscopyGastroscopyDuodenumBurns, ChemicalDuodenoscopyStomach DiseasesEndoscopes, GastrointestinalPeptic UlcerTreatment OutcomeEsophagoscopyEsophagusGastric MucosaDuodenal NeoplasmsEndoscopy, Digestive SystemGastrointestinal MotilityEsophagitisDigestive System Surgical ProceduresIleostomyStomach UlcerDyspepsiaGastritisIntestinal MucosaDigestive System Physiological PhenomenaGastric JuiceNeoplasms, Multiple PrimaryIntestine, SmallIleumMucous MembraneAdministration, OralBarrett EsophagusRetrospective StudiesProspective StudiesBiopsyHelicobacter InfectionsGastroesophageal RefluxAnti-Inflammatory Agents, Non-SteroidalHelicobacter pyloriLower Gastrointestinal TractNeoplasmsEarly Detection of CancerRisk FactorsTime FactorsOvarian NeoplasmsPostoperative ComplicationsLung NeoplasmsBreast NeoplasmsUpper ExtremityHematologic NeoplasmsIntestinesColonUrinary Tract InfectionsProstatic NeoplasmsNeoplasm MetastasisGene Expression Regulation, NeoplasticNeoplasm Invasiveness