ESTRO 2021 Abstract Book

S1178

ESTRO 2021

multivariable analyses.

Results 76 patients (51 with CNS and 25 with non-CNS tumors) with a median age of 9 years (2-25 years) were evaluated. The most common diagnoses were glioma, ependymoma, medulloblastoma, craniopharyngioma, and rhabdomyosarcoma. 77% of patients traveled more than 500 km, and 70% of them lived in metropolitan cities. Forty-four percent of patients had recurrent disease at presentation, and 15% had received a previous course of radiation. The median dose delivered was 54.8 CGE (30.6-70.4 CGE) to a median clinical target volume of 175 mL (range, 18.7-3,083.0 mL), with 37% of patients requiring concurrent chemotherapy (CCT). Acute grade 2 and grade 3 dermatitis, mucositis, and hematologic toxicity were noted in 45% and 2%, 34% and 0%, and 38% and 30% of patients, respectively. Grade 2 fatigue was noted in 26% of patients. On multivariable analysis, for CNS tumors, both CCT and craniospinal irradiation were independently associated with ≥ 2-grade hematologic toxicity, whereas among non-CNS tumors, a clinical target volume. 150 mL was associated with ≥ 2-grade fatigue, head and neck irradiation was associated with ≥ 2-grade mucositis, and CCT was associated with grade ≥ 2-hematologic toxicity. Conclusion This study demonstrates the safe implementation of a PBT program for children and young adults on the Indian subcontinent. Image-guided pencil beam scanning PBT in judiciously selected patients is feasible and can be delivered with acceptable acute toxicities. Purpose or Objective To evaluate the influence of radiation therapy (RT) dose and clinical variables on disease control and overall survival (OS) in patients treated for high-risk neuroblastoma (NB) at a single institution. Materials and Methods We developed a retrospective study of high-risk neuroblastoma patients who received RT as part of definitive management from January 2004 until May 2020 at our institution, Virgen del Rocio University Hospital (Seville, Spain). Kaplan-Meier method was used to analyze 'time-to-event' data. Results 39 children with neuroblastoma were treated at our institution with radical aim, 58.9% of patients were male (58.9%). The median age at diagnosis was 3.2 years (0.4-8.7). The median follow-up was 27 months (4-209). The most frequent primary location was the left adrenal gland (71.8%), and 33 patients had stage 4 or higher INSS stage (84.6%). 29 patients had nodal disease at diagnosis. Gross total resection was achieved in 69.2 % of patients. All patients received 21 Gy. 53.1% of patients had an unfavorable prognostic according to the INPC criteria (International Neuroblastoma Pathology Committee), the proto-oncogene n-myc was found amplified in 48.7% of the patients, and the MKI (Mitosis-karyorrhexis index) was high in 23.3% of that cohort. All recurrences have been treated with RT. 34 patients presented febrile neutropenia grade ≤ 4; 48.7% of patients presented anemia grade ≤ 4 and 8 had gastrointestinal acute toxicity (≤ Grade 2). Tumor recurrence was observed in 25 NB patients (64%). Median local relapse-free survival (LRFS) was 18.8 months, distant recurrence-free survival (DRFS) was 18 months and overall survival (OS) was 33 months. Left adrenal gland was associated with better prognosis (p=0.000). A significant decrease in overall survival (p value = 0.019) was found in the unfavorable INPC prognostic group. A significant decrease in OS was observed in patients with INSS ≥ 4 (p = 0.016) and patients with distant recurrence (p = 0.028) with no statistically significant differences observed in local relapses (p = 0.793). Also, we found no statistically significant differences in OS and other variables as n-myc amplification (p 0.087), the presence of metastasis at diagnosis (p = 0.080), positive lymph nodes (p = 0.113), high mitotic index (p = 0.310) or gross residual disease after surgery (p = 0.145). Conclusion A metastatic debut in most cases and unfavorable histology, lead to an uncertain prognosis despite multidisciplinary intervention in Neuroblastoma patients. RT with 21 Gy was safe and well-tolerated. All patients had excellent local control, and no disadvantage demonstrated for gross residual disease after surgery or lymph node positivity. The presence of INSS value ≥ 4, unfavorable histology according to INPC criteria or distant recurrence, have been independently associated with a worse prognosis in our study. PO-1436 Burden of pediatric oncology in radiotherapy department:A tertiary care center experience from India R. Madan 1 , T. Dey 2 , S. Goyal 2 , D. Bansal 3 , A. Trehan 3 , N. Peters 4 , D. Chatterjee 5 , N. Ballari 2 , D. Khosla 2 1 Post Graduate Institute of Medical Education and Research , Radiotherapy and Oncology, Chandigarh, India; 2 Post Graduate Institute of Medical Education and Research, Radiotherapy and Oncology, Chandigarh, India; 3 Post Graduate Institute of Medical Education and Research, Paediatric medicine, Chandigarh, India; 4 Post Graduate Institute of Medical Education and Research, Paediatric Surgery, Chandigarh, India; 5 Post Graduate Institute of Medical Education and Research, Histopathology, Chandigarh, India Purpose or Objective Radiotherapy (RT) plays an important role in the management of paediatric cancer patients. Due to lack of dedicated paediatric cancer registry, incidence of these cancers is not well established in low middle income countries (LMIC). We evaluated the burden of paediatric cancer patients treated in the department of radiotherapy and oncology at our institute over a period of 18 months. Materials and Methods The data was prospectively maintained in Microsoft excel spreadsheets. Paediatric cancer patients of age PO-1435 Toxicity and survival outcomes in high-risk neuroblastoma in childhood E. Gomis Selles 1 , P. Cabrera Roldán 1 , B.D. Delgado-León 1 1 Virgen del Rocio University Hospital, Radiation Oncology, Seville, Spain