Optical PD-L1 Imaging Using Quantitative Fluorescence Endoscopy in Locally Advanced Esophageal Cancer Using Durvalumab-680LT: a Multicenter Feasibility and Safety Study

Treatment of patients with locally advanced esophageal cancer (EC) is multidisciplinary and consists of neoadjuvant therapy followed by surgical removal of the esophageal tumor and potentially tumor positive lymph nodes. The beneficial effect of the addition of immunotherapy to improve response rates to current treatment strategies has been investigated response to, since only 16 to 43% of EC patients achieve a pathological complete response (pCR) after neoadjuvant therapy and a pCR is associated with better long-term outcomes. Unfortunately, not all patients respond to immunotherapy and the knowledge about biomarkers that predict response to therapy are required. A promising novel parameter is tumor programmed death-ligand 1 (PD-L1) expression, one of the immune checkpoints targeted by cancer immunotherapy. Studies performed in patients with various solid tumors demonstrate improved response to immunotherapy and survival benefit in patients with higher PD-L1 expression. Nonetheless, not all patients with high PD-L1 expression show benefit and some without expression do. Moreover, mostly biopsy-based tests are used to assess PD-L1 status, although these tests are prone to errors, partly due to heterogeneity in tissue expression. Novel methods are needed to gain more insight in the PD-L1 expression in order to better select patients who are likely to benefit from immunotherapy. The investigators hypothesize that quantitative fluorescence endoscopy using the tracer durvalumab-680LT targeting PD-L1 is a promising technique to investigate the heterogeneity of PD-L1 expression.