How to Create Evidence for the Integration of Local and Locoregional Treatments in Future Oncological Treatment Concepts?

BACKGROUND: While local treatment using more innovative technologies is increasingly applied in contemporary treatment of advanced cancer, its impact on outcomes is not well understood. METHODS: We reviewed the literature using PubMed and major oncology congress websites, and report here about the understanding of oligometastatic disease, about the role of primary tumor resection in metastatic disease, and about the value of cytoreduction and tumor ablation. RESULTS: The Achilless' heel of local treatment is the current lack of evidence of its efficacy. When considering how this lack of knowledge can be overcome, we arrive at three suggestions: First, adequately powered clinical trials must be performed to allow for the proper assessment of differences in survival outcomes. Second, the effect of local treatment on the biological evolution of the disease needs to be studied; analysis of circulating tumor DNA may help to assess these effects. Third and foremost, patient-reported outcomes like quality of life, symptom control, and satisfaction with treatment should define when to use and when to omit local treatment. CONCLUSIONS: Innovative trial designs in future oncology research will be required for assessing the true value of local and locoregional therapy.