[Oligometastasis in the gastrointestinal tract]

Oligometastasis describes an intermediate stage between localized and systemic tumor disease, in which a limited number of metastases with restricted organ involvement still appear amenable to local treatment. Despite its growing relevance and numerous publications, a unified definition for gastrointestinal (GI) tumors is lacking. The aim of this work was to summarize the existing definitions and current therapeutic standards for oligometastasis in the GI tract. Based on current studies and guidelines it becomes evident that local treatment is currently being investigated for gastric, esophageal, colorectal, pancreatic, hepatocellular and cholangiocellular carcinomas. Initial data suggest a possible improvement in survival through combined systemic and local treatment approaches. The results of most prospective studies are still pending. In the future, molecular markers and biological tumor characteristics are expected to contribute to better patient selection and further improve the integration of local treatment.