In this project, we aim to understand PET/CT-based imaging features and their molecular and clinical correlates pre/post therapy in gastroesophageal junction (GEJ) adenocarcinoma. In the DKTK-funded MEMORI trial we evaluated PET-directed chemo- (CTX) or salvage radiochemotherapy (CRT) and assembled sequential high-quality tumor tissue at PET/CT imaging time points pre/post therapy. The fully recruited trial, met its primary endpoint of improved negative surgical margins (R0 rate) upon salvage intensified CRT not responding to standard neoadjuvant CTX determined by PET response 14 days after CTX initiation. Salvage CRT also led to a highly increased rate of pathologic complete remissions (pCR) suggesting high local activity of CRT. However, an important result from the trial was distant recurrence in a subgroup of patients despite high R0 resection and pCR rates. Thus, current standard-of care PET/CT or histological diagnostics do not identify high- risk patients with bad outcome and their distinguishing tumor features remain unknown.

We here aim to investigate molecular subtypes and tumor metabolism patterns in the MEMORI patient cohort. We will focus on understanding therapy-induced molecular dynamics. We will correlate these findings with PET-CT derived metabolic and anatomical imaging data using standard (SUVmax/mean) and advanced (radiomics) techniques leveraging the infrastructure provided by the Joint Imaging Platform (JIP) to perform an integrated analysis of clinical, molecular and imaging data. The available clinical and multimodal imaging data combined with available tumor tissue before, during and after neoadjuvant therapy are a unique opportunity to address fundamental questions of imaging and tissue- based features in tumor metabolism, heterogeneity and therapy response.

A final project summary will be provided.