259 Complete Pathological Response to Pembrolizumab in Locally Advanced Oesophageal Cancer: A Case Study

Abstract Background Pembrolizumab was approved by NICE in 2021 for use with platinum- and fluoropyrimidine-based chemotherapy in patients with locally advanced unresectable, or metastatic PD-L1 expressing carcinoma of the oesophagus. We describe a case of locally advanced oesophageal adenocarcinoma in which treatment with pembrolizumab resulted in a complete pathological response. Case Presentation A 70-year-old gentleman presented with T3N2M0 moderately differentiated lower oesophageal adenocarcinoma. He underwent neoadjuvant chemotherapy with fluorouracil, oxaliplatin, and docetaxel (FLOT), resulting in a partial radiological response. Upon completion of neoadjuvant therapy, the tumour was deemed operable, however the patient initially declined surgery. Surveillance imaging at three months demonstrated disease progression. Eight cycles of carboplatin and capecitabine were then completed. Although initially radiologically stable, subsequent disease progression resulted in dysphagia. Pembrolizumab was started and continued for six months. Three months into treatment, worsening dysphagia prompted oesophageal stenting, with only temporary symptomatic relief and nasojejunal feeding was commenced. Restaging PET-CT demonstrated operable disease, with focal uptake adjacent to the primary tumour and ongoing left gastric node avidity. The patient underwent an uncomplicated robotic-assisted oesophagogastrectomy. Final histopathology revealed a complete pathological response, with no residual tumour, dysplasia, or lymph node involvement. Conclusions This case demonstrates the use of pembrolizumab in the management of patients with PD-L1 expressing oesophageal carcinoma and highlights the evolving role of immunotherapy in oesophagogastric cancer treatment.