Definition and management of intra-abdominal metachronous oligometastatic pancreatic cancer: a systematic review

Five-year survival rates of pancreatic ductal adenocarcinoma (PDAC) remain poor at approximately 3 per cent1. Of those suitable for surgery, recurrence occurs in almost 85 per cent2, some of which is widespread disease and some more limited. The oligometastatic state is defined as a transitional zone between localized and widespread systemic disease, where cancer has spread beyond the original site, but is not widely disseminated3. Treatment of oligometastases may lead to a prolonged survival in several different cancers, although this is contentious4. For example, surgical treatment of metachronous oligometastatic disease is well established in colorectal and neuroendocrine tumours4–7. Conversely, there is limited evidence in the context of PDAC8–10. To help classify oligometastatic disease, the European Organisation for Research and Treatment of Cancer (EORTC) published consensus definitions in 202011, although it is uncertain if these are being adopted in research or clinical practice. This study aims to systematically review existing literature to summarize the definitions used for metachronous oligometastatic PDAC and treatment strategies and outcomes for patients with intra-abdominal oligometastatic PDAC; to facilitate progress in this field. © 2024 John Wiley and Sons Ltd. All rights reserved.