Primary Tumor Resection for Metastatic Colorectal, Gastric and Pancreatic Cancer Patients: In Search of Scientific Evidence to Inform Clinical Practice

Simple Summary Oncology practice in gastrointestinal tumors is moving toward therapeutic algorithms comprising multiple systemic options integrated with loco-regional strategies, such as surgery. This paradigm holds true for metastatic colorectal cancer, as well as upper gastrointestinal neoplasms, where the role of the resection of the primary tumor, with or without the administration of systemic therapies and metastasectomy, has been a matter of debate. In our review paper, we discuss the available randomized and retrospective evidence supporting surgery in the metastatic setting of colorectal, gastric and pancreatic cancers, with the aim to grant the clinicians with an up-to-date state of the art on this subject. The management of the primary tumor in metastatic colorectal, gastric and pancreatic cancer patients may be challenging. Indeed, primary tumor progression could be associated with severe symptoms, compromising the quality of life and the feasibility of effective systemic therapy, and might result in life-threatening complications. While retrospective series have suggested that surgery on the primary tumor may confer a survival advantage even in asymptomatic patients, randomized trials seem not to definitively support this hypothesis. We discuss the evidence for and against primary tumor resection for patients with metastatic gastrointestinal (colorectal, gastric and pancreatic) cancers treated with systemic therapies and put in context the pros and cons of the onco-surgical approach in the time of precision oncology. We also evaluate current ongoing trials on this topic, anticipating how these will influence both research and everyday practice.