Stereotactic radiosurgery in the era of novel systemic therapy for lung cancer brain metastases

Abstract

The emergence of novel systemic therapies has spurred a dramatic paradigm shift in lung cancer treatment. Research has revealed greater intracranial efficacy in targeted agents and immune checkpoint inhibitors (ICI) compared to conventional chemotherapy. Concurrently, advances in stereotactic radiosurgery (SRS) have contributed to the increased use of this highly localized, minimally-invasive treatment modality for local tumor control. In this era of precision medicine, the combination of these novel agents and SRS demands further prospective exploration - particularly as questions regarding their sequence of administration and the risk of neurotoxicity remain unanswered. Presently, although data are limited and largely retrospective, literature supports the concurrent administration of ICI and radiation, with no observed increases in immune-related adverse events or acute neurologic toxicities. In the case of patients with driver mutations, newer generations of tyrosine kinase inhibitors (TKI) display improved intracranial efficacy and are currently preferred alone upfront in patients with asymptomatic brain metastases (BM) due to lack of data. Evidence of combining TKI and SRS is limited with mixed results. In this review, we explore the evidence regarding the use of novel systemic agents and SRS for treatment of lung cancer BM. Clinical practice will continue to be refined as larger, prospective studies yield results