Results of a questionnaire regarding practice patterns for the diagnosis and treatment of intracranial radiation necrosis after SRS.

Although stereotactic radiosurgery (SRS) is an effective treatment option for patients with brain tumors, its increased use has raised concern for increased incidence of radiation necrosis (RN). No established standard or guidelines exists regarding non-invasive techniques to diagnose or treat RN. This study was conducted to assess current patterns of evaluation and treatment of RN among physicians who treat intracranial malignancies. A questionnaire consisting of 20 questions was sent to 3,041 members of the American Society for Radiation Oncology (ASTRO) and the Society for Neurologic Oncology (SNO). Questions addressed demographics, utilization of SRS, perceptions regarding RN diagnosis treatment, approach to steroid-refractory RN, and management of two clinical scenarios using Kwiksurvey© software. The survey response rate was 8.74 % (266/3,041). Most respondents practice in an academic and/or university setting (62 %) at a facility that performs SRS (94 %) with a variety of systems. The number of annual cases performed at the participant's institution varied from <50 to >400, with a wide degree of variability. Most respondents practice at an institution that performs 50-100 cases/year (28 %). The most common range of symptomatic RN seen in clinical practice was 1-5 % (61 %). Most respondents reported that asymptomatic RN occurs in 6-10 % (33 %). Favored non-invasive diagnostic mechanisms were clinical evaluation (37 %) and MRI (19 %). In response to a clinical scenario depicting an asymptomatic patient post-SRS for brain metastasis with an enlarging lesion and edema at the treatment site, most respondents felt the image represented RN or a combination of RN and tumor progression. Most (58 %) favored short-term follow-up with repeat MRI. Ninety-three percent of the respondents initiated steroids as a first-line approach if patient was to develop symptoms. Steroids were the preferred first therapy in symptomatic patients on initial follow-up (81 %). In steroid-refractory patients, most recommend surgical intervention (63 %). Most physicians who responded to this questionnaire believe that post-SRS RN is uncommon (≤10 % of cases). The approach to establish the diagnosis of RN is variable. Steroids are the most commonly utilized first-line treatment for suspected RN. Considerable variation exists in the management of steroid-refractory RN. Additional studies are required to establish guidelines for evaluation and treatment of RN.