Outcomes of whole-brain radiation with simultaneous in-field boost (SIB) for the treatment of brain metastases.

Purpose: Prospective studies have demonstrated increased local control with the addition of a radiosurgery (SRS) boost to whole-brain irradiation (WBRT) in patients with brain metastases. However, the clinical application of SRS boost can be limited by several factors, including tumor size, numbers of lesions, and high cost of care. Here, we investigate the use of WBRT with a simultaneous integrated boost (SIB) to visible lesions in patients with brain metastases.

Materials: From 2011 to 2016, patients were prospectively enrolled and prescribed a dose of 25 or 37.5 Gray (Gy) WBRT with a SIB dose of 45 or 52.5 Gy to the gross lesions in 10 or 15 fractions, respectively. All plans were optimized for dose coverage of the whole brain and lesions using volumetric arc therapy (VMAT). Comprehensive neurocognitive and quality of life assessments were conducted at baseline and at follow-up.

Results: Thirteen patients were treated on this protocol. The 1-year local control rates were 92% at the patient level, and 98.6% at the lesion level. The overall 1-year intracranial control was 46%. Patients had no significant declines in Mini-Mental State Examination (MMSE), Hopkins Verbal Learning Test-Revised (HVLT-R), and Medical Outcomes Study (MOS) Cognitive Functional status scores pre- and post-treatment.

Conclusion: WBRT with SIB to gross lesions using VMAT planning appears to be safe and effective in the treatment of brain metastases without significant cognitive decline. This treatment strategy should be considered in those patients with a high number of metastases or ones not amenable for radiosurgery.

Clinical Trial Registration Code: NCT01218542.