Inconsistencies in the predictive value of PD-L1 in metastatic gastroesophageal cancer

Gastro-oesophageal cancers pose a sizeable global health burden and contribute to a substantial number of cancer-related deaths worldwide. Historic therapeutic approaches such as chemotherapy have limited efficacy, especially in advanced cases. The addition of immunotherapy, specifically anti-PD-1 immune checkpoint inhibitors, to chemotherapy has shown a survival benefit across multiple tumour types, including gastro-oesophageal cancers. As data have accumulated from large global trials evaluating immune checkpoint inhibitors, ground truths and unanswered questions have emerged.