A Case of Metastatic Pancreatic Adenocarcinoma in Complete Remission Using Chemotherapy and Immunotherapy

Among the various types of cancer, pancreatic cancer is considered to have a particularly grim prognosis. Treatment includes surgery, chemotherapy, or both. While the role of immunotherapy is well-studied in many types of cancer, such is not the case with pancreatic cancer. A 49-year-old female presented to the oncology clinic following a biopsy of a pancreatic mass. CT-guided needle biopsy of the mass demonstrated moderately differentiated pancreatic adenocarcinoma. Positive emission tomography-computed tomography (PET-CT) revealed metastases to the liver. She was started on chemotherapy with FOLFIRINOX (leucovorin calcium, 5-fluorouracil, irinotecan hydrochloride, oxaliplatin) and demonstrated over 60% reduction in the size of liver metastases within three months. PET-CT four months after initiation of chemotherapy revealed no focal avid fluorodeoxyglucose (FDG) uptake in the liver, and the pancreatic body mass was stable in size at 3.0 cm with stable standardized uptake value (SUV) max at 2.4, only slightly elevated from 1.9 on the previous scan. Further treatment with chemotherapy was halted after 18 cycles due to side effects. With the patient's tumor being epidermal growth factor receptor (EGFR) negative, mismatch repair (MMR) negative, 3% tumor cells PD-L1 positive with 10% tumor-associated immune cells positive, treatment with pembrolizumab was started. Follow-up PET-CTs over the next several months confirmed the patient was in complete remission from metastatic pancreatic cancer. At the time of the report, the patient had a durable response of three years. We report a rare case of complete remission of metastatic pancreatic adenocarcinoma treated with chemotherapy, followed by immunotherapy. With emerging targets for modification of tumor microenvironment, immunotherapy must be further explored in the treatment of pancreatic cancer.