Esophagogastric JunctionAdenocarcinomaStomach NeoplasmsEsophageal NeoplasmsGastroesophageal RefluxCardiaStomachHernia, HiatalEsophagusBarrett EsophagusEsophagoscopyEsophageal DiseasesManometryEsophageal pH MonitoringMetaplasiaEsophagectomyFundoplicationEsophageal AchalasiaGastrectomyGap JunctionsFluorouracilTreatment OutcomeCisplatinIntercellular JunctionsTight JunctionsEsophagitisAntineoplastic Combined Chemotherapy ProtocolsNeoplasm Staging