P20.09.A FRACTIONATED STEREOTACTIC RADIOTHERAPY (FSRT) AS A TREATMENT FOR TRIGEMINAL SCHWANNOMAS

Abstract

Abstract BACKGROUND Trigeminal schwannomas (TS) represent 1-8% of all intracranial schwannomas and 0.1-0.5% of all intracranial tumors Treatment strategies are mainly based on limited published data and case reports. The most common treatment is surgical resection. However, it can rarely be completed. Fractionated stereotactic radiotherapy (FSRT) has the potential to be a valuable and safe alternative to control growing or symptomatic TS. The aim of this review is to analyze clinical RESULTS , toxicity and tumor control rates obtained with this technique when treating this pathology in our short series of cases. MATERIAL AND METHODS Medical records of 18 patients treated from January 2007 to December 2018 were reviewed. 15 of them presented symptoms at the moment of diagnosis (83.3%) and the remaining 3 were radiological findings. Surgery was previously performed in 2 cases. Regarding radiotherapy scheme, all patients received 1.8-2Gy daily fractions to a median of 50,0 Gy. The median follow-up time was 62.7 months. RESULTS The outcome after radiotherapy was favourable in 16 of 18 patients (88.8%), clinical improvement was achieved in 52.94% while stability of symptoms was reached in 35.29%. Tumor growth was controlled in 82.35% of cases, even with tumor decrease observed in 5.88%. Acute toxicity was detected in 23.53% and it consisted in increased pain, sensitive alterations and diplopia. All well tolerated with adjusted corticoids and pain medication scheme. Clinical worsening and radiographic progression was shown in 2 out 17 patients and surgery was needed as salvage treatment in both cases (11.76%). However, one of them presented these outcomes in a period in which pseudoprogression could not be excluded (less than 2 years after treatment). CONCLUSION FSRT such as primary or adjuvant treatment accomplishes good clinical results and tumoral control, being an alternative for those patients with comorbidities not suitable for a surgical treatment or who preferred a non-invasive treatment. Regarding toxicity, FSRT is mainly a well tolerated treatment among patients. Prospective multicenter studies should be run in order to accomplish statistically significant results. Also, it is the second case series that reports the flare effect.