How to optimize the incorporation of immunotherapy in trials for oligometastatic non-small cell lung cancer: A narrative review

Patients with oligometastatic disease (OMD) non-small cell lung cancer (NSCLC) are considered as a subgroup of metastatic NSCLC that can obtain long-term survival or even cure. Oligometastatic refers to a state of a limited number of metastases in a limited number of organs. In clinical guidelines it is stated that patients with oligometastatic NSCLC can benefit from the addition of local radical therapy (LRT) to systemic therapy. With the introduction of minimally invasive surgery, advances in interventional radiology and stereotactic radiotherapy (SRT), LRT is becoming feasible for more and more patients. Furthermore, the introduction of immune checkpoint inhibitors (ICI) in the treatment landscape of advanced NSCLC has improved the survival of these patients. Importantly, the use of ICI in combination with LRT is also of interest in the subgroup of NSCLC patients with OMD. For example, it has been suggested that SRT may synergize with ICI as several preclinical studies reported an increased tumor antigen release, improved antigen presentation, and T-cell infiltration in irradiated tumors. In this narrative review, we describe the current evidence of immunotherapy treatment in OMD NSCLC, with a focus on future trial design and problems that need to be addressed.