Exceptional Eight-year Response to Stereotactic Radiosurgery Monotherapy for Multiple Brain Metastases

Breast cancer represents the second leading cause of brain metastases in women. Once diagnosed, brain metastases have been associated with a rapidly progressive and universally poor prognosis. Breast cancer patients, particularly those with advantageous disease characteristics, may achieve extended survival. This extended life expectancy highlights the importance of effective intracranial treatments that minimize treatment-related late toxicity. Whole brain radiation therapy (WBRT) remains a standard of care palliative option; however, concerns remain regarding the late neurocognitive effects. Stereotactic radiosurgery (SRS) provides dose-escalated radiation therapy over a shortened course, maintaining equivalent survival and minimizing normal brain tissue exposure. Herein, we present a breast cancer patient who demonstrated an exceptional response and remained functionally independent following 12 SRS courses targeting 14 unique brain metastases over eight years. The case illustrates the efficacy of SRS alone, as well as the comparable utility of multiple SRS treatment techniques (Gamma Knife (AB Elekta, Stockholm, Sweden), CyberKnife (Accuray, Sunnyvale, California), and TrueBeam (Varian Medical Systems, Palo Alto, California)).