HER2-positive Gastroesophageal Junction Clinical Trials in Aalst

A Study of Trastuzumab DeRuxtecan for Patients With Advanced HER2-pOsitive GaStric or GastroesoPhageal Junction AdEnocarcinoma Who Have Received a PrIor Trastuzumab-based Regimen Accompanied by a Disease RegistrY of Patients Treated With Conventional Therapies (PROSPERITY)