Background: Pancreatic cancer oligometastatic to the liver represents a distinct subset of advanced disease, presenting a limited number of metastases in a single site. First-line chemotherapy is considered the standard of care, with a poor overall prognosis. However, the optimal strategy for oligometastatic patients presenting response or stability after treatment is unclear. In selected patients, surgical resection is associated with prolonged survival, according to retrospective series. The aim of this randomized clinical trial is to compare the efficacy and safety of surgery versus observation or continuation of chemotherapy in patients with resectable pancreatic cancer oligometastatic to the liver with stable disease or response after first-line chemotherapy.
Methods: The study is a phase-2 multicentric randomized controlled trial with 1:1 allocation ratio. Patients diagnosed with pancreatic cancer and a limited number (up to 3) of liver metastases, with no evidence of extrahepatic disease, who received systemic chemotherapy as the initial treatment and with disease response or stability after therapy will be considered eligible patients. Patients will be randomized to either Arm A (surgery) or Arm B (observation or continuation of chemotherapy). The primary outcome will be overall survival at two years, with secondary outcomes including progression-free survival, treatment-related adverse events, quality of life and translational analyses.
Discussion: This randomized controlled trial will evaluate the role of surgery in pancreatic cancer oligometastatic to the liver after response or stability to first-line chemotherapy. While systemic therapy remains the standard of care, selected patients may benefit from surgical resection. By comparing surgery to observation or continuation of chemotherapy, the SONAR trial aims to fill a critical gap in treatment strategies and potentially refine the management of this challenging disease.
Trial registration: The trial has been registered at ClinicalTrials.gov on 15/11/2024 before inclusion of the first patient (NCT06690528).
Keywords: Combined surgery for metastatic pancreatic cancer.; Conversion surgery; Neoadjuvant therapy for oligometastatic pancreatic cancer; Pancreatic cancer; Pancreatic cancer metastatic to liver; Pancreatic cancer oligometastatic to liver; Resectable liver metastasis in pancreatic cancer; Resectable pancreatic cancer.
© 2026. The Author(s).