Oligometastatic non-small cell lung cancer: a narrative review of stereotactic ablative radiotherapy

Non-small cell lung cancer (NSCLC) is the most common and deadly malignancy in the United States. A significant portion of these individuals can present with or later develop metastatic NSCLC (mNSCLC). These patients typically do not survive more than two to three years after diagnosis despite the use of systemic therapies; however, there are individuals with low burden mNSCLC (oligometastatic disease) who can potentially be cured with the use of aggressive local therapies-such as stereotactic ablative radiotherapy (SAbR)-in conjunction with or without systemic therapy. Oligometastatic disease represents an intermediate state prior to the development of widespread metastases. SAbR has been shown to be an effective modality for treating patients with oligometastatic NSCLC. The combination of immunotherapy and SAbR likely represents one of the most effective while still tolerable therapies in this patient population. There are other subtypes of oligometastatic disease, including oligoprogressive disease which are amenable to SAbR. The current literature supports the use of SAbR in this population to increase the time of a patient's current systemic therapy; however, there are prospective studies evaluating the efficacy of treatment on progression free survival (PFS).