Results of Radiation Therapy as Local Ablative Therapy for Oligometastatic Non-Small Cell Lung Cancer

SIMPLE SUMMARY: Metastatic lung cancer represents a heterogeneous population of patients. Up to half of patients with metastatic lung cancer may be oligometastatic, an intermediate step between localized disease and widespread metastasis that is characterized by a limited number of metastatic deposits. Patients with oligometastatic lung cancer may benefit from local ablative therapy (LAT) directed at metastatic deposits in addition to standard-of-care systemic therapy. Radiation therapy is one option for LAT in lung cancer. This review will discuss the studies that have established the safety and efficacy of radiation therapy for oligometastatic lung cancer. ABSTRACT: Oligometastatic cancer is characterized by a limited number of metastatic deposits. Compared with lung cancer patients who have more widespread disease, oligometastatic lung cancer patients have more favorable survival outcomes. Therefore, it has been hypothesized that local ablative therapy (LAT) directed at the metastatic deposits in addition to standard-of-care systemic therapy may further improve survival outcomes in oligometastatic lung cancer patients. One LAT modality that has been utilized in oligometastatic lung cancer is radiation therapy. In particular, ultra-hypofractionated radiotherapy, also known as stereotactic body radiotherapy (SBRT), has been shown to provide excellent local control with a favorable safety profile. Here, we reviewed the retrospective studies and prospective trials that have deployed radiation therapy as LAT in oligometastatic lung cancer, including randomized studies showing benefits for progression-free survival and overall survival with the addition of LAT. We also discuss the impact of targeted therapies and immunotherapy on radiation as LAT.