Continuous Regression of Metastatic Pancreatic Adenocarcinoma after Suspending Chemotherapy: A Case Report

Our patient's rare clinical course raises questions including the optimal next steps in treatment, such as continued observation or local treatment such as surgical resection. The decision to continue observation results from our belief that minimal disruption of the tumor microenvironment may allow for continued control and cancer regression. More laboratory and clinical studies are imperative to understanding the physiological basis of sustained tumor regression after chemotherapy discontinuation and may impact real-world clinical decision-making. Additionally, the definition of spontaneous tumor regression may need revision to distinguish between prolonged therapeutic response and regression due to immunogenic features in the absence of prior therapy.