Effect of Radiosurgery Alone vs Radiosurgery With Whole Brain Radiation Therapy on Cognitive Function in Patients With 1 to 3 Brain Metastases

Abstract

Approximately 30% of patients with cancer develop brain metastases, and the incidence of these lesions is rising.^1,2 Most patients present with oligometastatic disease, which is to say limited intracranial metastases, usually defined as 1 to 3 lesions.³ Stereotactic radiosurgery (SRS) is an effective and commonly used treatment for brain metastases, but intracranial tumor progression is frequent after SRS alone, primarily because of the development of new metastatic lesions.^1,4,5 Previous randomized clinical trials (RCTs) have consistently demonstrated improved intracranial tumor control with the addition of whole brain radiotherapy (WBRT) to SRS for cerebral oligometastases; the clinical significance of this observation, however, remains unclear. None of these prospective analyses have demonstrated a survival advantage to adjuvant WBRT, and a single RCT has reported a survival disadvantage.^1,4,5 Additionally, central to this issue is whether tumor progression anywhere in the brain is more detrimental to a patient’s well-being than the potential deterioration of cognitive function and quality of life (QOL) associated with WBRT.^4,6,7 Because more than 200 000 individuals in the United States alone are estimated to receive WBRT each year,⁸ it is important that the potential benefits and risks of adjuvant WBRT be clearly defined. To address ongoing knowledge gaps, N0574, a multi-institutional RCT, investigated the role of adjuvant WBRT in patients with 1 to 3 brain metastases treated with SRS (see trial protocol in Supplement 1).