Abstract
Currently, no consensus exists regarding the definition of oligometastatic pancreatic ductal adenocarcinoma, its necessary diagnostic measures, and potential treatment approaches. To address these knowledge gaps, the OligoPanc project brought together an interdisciplinary group of experts to establish consensus using a modified Delphi process and clinical vignettes. Participants agreed that the number of metastatic lesions and the number of affected organs are key elements in defining oligometastatic pancreatic ductal adenocarcinoma. Specifically, up to three lesions in a single organ, either the liver or the lung, define oligometastatic pancreatic ductal adenocarcinoma and could be either synchronous or metachronous. Necessary diagnostics include a triple-phase contrast-enhanced CT scan of the chest and abdomen and MRI of the liver with a hepatocyte-specific contrast agent. In unclear cases, [18F]fluorodeoxyglucose-PET CT or MRI can be considered. A multidisciplinary tumour board is essential. Patient-intrinsic factors, including age, do not define oligometastatic disease but should be considered for any treatment decision. Systemic treatment before any local consolidative treatment, including surgery, stereotactic ablative radiotherapy, or other locally ablative techniques, is mandatory. The proposed definition should be incorporated into future trials to improve comparability and enable validation.