Abstract Book

S685

ESTRO 37

Conclusion Radiotherapy decreases recurrence in patients with atypical meningiomas and subtotal resection. In our study, despite a high percentage of Simpson I and II resections, there was a high incidence of recurrence. Therefore, it is possible that not only patients with subtotal resections benefit from treatment with adjuvant radiotherapy, but that some patients with total resections, well selected by risk factors (like a bone invasion, brain invasion, necrosis or others risk factors) may also benefit. EP-1236 IMRT with SIB in patients affected by malignant gliomas: a systematic review G. Zanirato Rambaldi 1 , G. Siepe 2 , S. Cammelli 2 , G. Macchia 3 , F. Deodato 3 , S. Cilla 4 , G.P. Frezza 5 , A.G. Morganti 2 1 Radiology Unit- Department of Experimental- Diagnostic and Specialty Medicine – DIMES, University of Bologna, Bologna, Italy 2 Radiation Oncology Center- Department of Experimental- Diagnostic and Specialty Medicine - DIMES, University of Bologna, Bologna, Italy 3 Radiotherapy Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Campobasso, Italy 4 Medical Physics Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Campobasso, Italy 5 Radiation Oncology Unit, Bellaria Hospital, Bologna, Italy Purpose or Objective Malignant gliomas represent the most common primary brain tumors in adults, with poor outcome and survival. The pattern of failure after definitive or post-operative radiation therapy (RT) is primarily local recurrence, and this could be due in part to inadequate therapeutic doses limited by the tolerance of normal tissues to irradiation. The use of intensity modulated RT (IMRT) with its possibility of minimizing adjacent tissue dose and of focal increasing primary tumor dose might lead to better outcome and survival. The aim is to present a systematic review of clinical results on overall survival (OS) and disease free survival (DFS) after IMRT with simultaneous integrated boost (SIB) in gliomas. Material and Methods A systematic review of published literature was performed on PubMed and the Cochrane Library. Retrospective and prospective clinical trials reporting outcome in patients treated with IMRT-SIB have been analyzed. RT doses were converted in biologically 2Gy- equivalent doses (EQD2) to better compare the results. Results A total of 220 patients from 9 studies were included. These studies are characterized by small sample size and different RT doses and fractionations, but with similar planning analysis. In all studies, the gross tumor volume was defined as the contrast-enhancing residual tumor on the T1-weighted pre-RT brain magnetic resonance imaging scan plus the entire surgical cavity. This volume was the target of focal dose increase. Mean EQD2 dose of 72.5 Gy (range 60-101.3) was delivered. Acceptable toxicities were reported, with 8/220 (6,3%) patients experiencing severe acute (≥ G3 ) toxicity and 5/220 (2,27%) patients experiencing severe late (≥ G3 ) toxicity. Mean OS and PFS were respectively 18.2 (range 14.8- 22.4) and 10.7 (range 7.8-12) months. However local failure is still the most common site of recurrence. Conclusion IMRT-SIB contribute to the control of the disease, resulting in satisfactory OS and PFS, with acceptable toxicities.

EP-1237 Radiosurgery re-irradiation in trigeminal neuralgia: a clinical case C. Meneses Dias 1 , A. Pires 1 , J. Gagean 1 , A. Aguiar 1 , S. Conde 1 1 Instituto Português de Oncologia do Porto Francisco Gentil- EPE, Radioterapia Externa, Porto, Portugal Purpose or Objective Trigeminal Neuralgia (TN) is a chronic condition that manifests clinically as bouts of electric shock-like facial pain. The disease has an incidence of 12/100,000 cases/year and is more common in females (2:1). Although it can occur in any age, 90% of cas es affect individuals older than 40 years. While pharmacological agents are the first line of treatment, surgery has an important role in refractory cases and/or in cases of intolerance to medical therapy. Radiosurgery (SRS) comprises a non-invasive, well- tolerated alternative treatment option. Therapeutic success rates for radiosurgery in TN are as high as 71% immediately after treatment and about 64% at 5 years. Recurrence rate at 3 years is about 25%. In theses cases, re-irradiation is considered a valid option. We report a case of TN treated with SRS re-irradiation. Material and Methods The patient’s digital clinical records were consulted. A bibliographical research was made and a brief literature review is provided. Results A 31-year-old female patient was admitted to our Institution in 2014 with refractory left-sided TN with 4- year evolution. Previous medical treatment with multiple combinations of pharmacological agents had been attempted with only partial or limited clinical response. Surgical treatment was offered, which the patient refused. The patient was treated with SRS to the Root Entry Zone (REZ), with a dose of 80Gy/1fr prescribed to a single point, with 4mm cone arches in October 2014. Treatment was well tolerated and clinical improvement was noted. In early 2017, due to clinical relapse with refractory facial pain and significantly increased amounts of prescribed analgesic therapy, as well as hyposthesia of the V1 e V2 branches, the patient was again proposed for surgery, which she refused one more time. As such, SRS re-irradiation was proposed, which was performed in May 2017 with a total dose of 60Gr/1fr to the REZ, slightly anterior to the previous irradiated point, with eight 4mm cone arcs. Last clinical observation showed partially controlled pain with sustained left V2 hyposthesia. Conclusion TN is a chronic pain condition. For many patients, medical therapy is not sufficient for adequate pain control. Radiosurgery proves to be an effective, well- tolerated therapeutic option and can be used in cases of recurrent disease after prior irradiation. However, not every patient seems to benefit with this therapeutic option and it remains unclear which subgroup would profit with this approach. EP-1238 Validation of the GPA index in brain metastasis treated with Stereotactic radiosurgery S. Flamarique Andueza 1 , M. Rico Osés 1 , I. Visus Fernández de Manzanos 1 , M. Campo Vargas 1 , M. Barrado Los Arcos 1 , A. Martín Martínez 1 , M. Rodríguez Mendizábal 1 , S. Pellejero Pellejero 2 , F. Mañeru Cámara 2 , E. Martínez López 1 1 Complejo Hospitalario de Navarra, Oncología Radioterápica, Pamplona, Spain 2 Complejo Hospitalario de Navarra, Radiofísica, Pamplona, Spain