Stereotactic Radiosurgery for Multiple Brain Metastases: Two Cases of Preserved Quality of Life

Abstract

Brain metastases are the most common intracranial tumors in the adult population and have been historically treated with whole brain radiation therapy (WBRT). However, as medical advances improve life expectancy, stereotactic radiosurgery (SRS) has replaced WBRT as the standard of care for limited (one to three) brain metastases due to the relative sparing of neurocognitive function (NCF) and therefore quality of life (QoL). The use of SRS has been less documented in the case of multiple (four or more) brain metastases, with literature limited to non-randomized studies showing comparable survival and local control. In this series, we detail the case of two individuals who received SRS at our institution for multiple brain metastases and demonstrated remarkable response. The first patient is a 78-year-old woman who received Gamma Knife (GK) treatment to 17 lesions at our institution. This patient responded very well to treatment and maintains an excellent quality of life, with no deficits on serial neurological examination as she continues to travel and drive for ridesharing businesses. The second patient is an active 44-year-old woman who received SRS to 24 lesions at our institution. The patient has now been free of intracranial failures for two years and continues fulfilling her love for travel and long-distance biking. SRS is emerging as an acceptable alternative to WBRT in treating multiple brain metastases due to its preservation of NCF. Because omission of WBRT may lead to increased probability of distant brain metastasis failure, it is critical to follow these patients closely with frequent neuroimaging. In the event of a failure, it is also possible to use SRS salvage therapy with good response. Some patients who receive SRS alone demonstrate exceptional outcomes with excellent QoL, and it is possible that certain prognostication factors such as performance status, tumor histology, and tumor volume may play a role in identifying these patients. The decision to treat a patient with SRS alone for multiple brain metastases should be made carefully with consideration of systemic therapeutic options, overall prognosis, and the patient's goals of care, with adherence to a careful follow-up plan by the physician and patient.

Keywords: brain metastases; quality of life; radiation oncology; stereotactic radiosurgery; survivorship.

Figure 1. Patient PG presented with 17 lesions at the time of treatment planning.

MRI of the brain including A) a right frontal lesion and a left frontal lesion, B) a right anterior frontal lesion and left posterior frontal lesion, C) a left frontal lesion and a left parietal lesion, and D) left temporal cluster. All these lesions were treated with 18 Gy to various isodose lines in one to three shots. On the most recent MRI of the brain on November 2017 (E-H), all treated lesions have disappeared and there were no new lesions concerning for metastatic disease. MRI - magnetic resonance imaging.

Figure 2. Patient MK - MRI of the brain.

Patient MK initially presented in 2013 with one resection cavity and A) three untreated lesions. On her September 2014 GK MRI, her treated lesions were stable (B, blue arrow)—including a lesion treated in January 2014 (C, blue arrow); however, she presented with nine lesions, four of which are shown here (C, D, red arrows), which were treated with 20 Gy to various isodose lines, though two brainstem lesions were treated with a lower dose of 18 Gy to minimize the risk of brainstem injury (D, red arrows). In March 2015, she had persistent enhancement of a lesion (E) with surrounding edema (F), which underwent surgical resection and demonstrated persistent disease. On the most recent scan, all lesions are resolved or stable (G, H). MRI - magnetic resonance imaging, GK - Gamma Knife.