Hyperprogression in PDL1 Expressive, Recurrent Gastroesophageal-junction Adenocarcinoma After Pembrolizumab.

Hyperprogression is a pattern of accelerated tumor growth noted uncommonly after the use of immune checkpoint inhibitors in some patients. We present a 56-year-old female with gastroesophageal junction (GEJ) adenocarcinoma who was initially treated with neoadjuvant radiation and chemotherapy with carboplatin and paclitaxel, followed by esophagogastrectomy and postoperative FOLFOX chemotherapy. After a stable two-year course, she was noted to have recurrence at the GEJ which was biopsy confirmed. She was started on pembrolizumab, after which she developed several new metastases noted on the PET/CT. Lesions were noted in iliac bones, spine, retroperitoneal lymph nodes, hilar nodes, mediastinum, and lungs. Postdiscontinuation of the pembrolizumab, she received six cycles of paclitaxel with ramucirumab and showed remarkable improvement on the next imaging scan with resolution of osseous lesions, lung nodules and significant improvement in hilar, mediastinal, and retroperitoneal lymph nodes. We hope that this case report sheds further light on this uncommon complication of immune checkpoint inhibitors.