ESTRO 37 Abstract book

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ESTRO 37

Conclusion When compared to VMAT, PBS-PT presents equal target coverage. In addition, a reduction of the dose to the OARs and body is achieved with PBS-PT. Thus, chances of reducing radiotherapy side effects might increase with PBS-PT over VMAT. Moreover, sparing of the OAR and body can be achieved while not accounting for the constraint to the VB in the planning. Thus, clinical guidelines concerning the VB should be established for these tumor sites. J.S. Ali 1 , L.Y. Mula-Hussain 1 , S. Othman 2 , K. Marif 2 , N. Othman 2 , S. Ali 2 , B.M. Muhsin 2 , S. Majid 2 , A.H. Gendari 2 , A. Kamal 2 1 Zhianawa Cancer Centre, Radiation Oncology, As sulaimanyah, Iraq 2 Zhianawa cancer Center, Radiation Oncology, Sulaymaniyah, Iraq Purpose or Objective The aim of the study is to evaluate the mode of the clinical presentations, staging distribution and the survival outcomes of WT patients in our institution. Material and Methods Retrospective study on 50 WT patients who had been managed at our oncology complex in Northern Iraq in ten years (from January 2007 to January 2017). Comparison with other relevant published literature was accomplished. Statistical Package for Social Science (SPSS) software (version 20.0) is used while the survival outcomes were analyzed by Kaplan-Meier method. Results 50 children (29 females and 21 males) were analysed. Median age at time of diagnosis was 2.7 years (ranged 0.7-10.1). The distributions of stages were as follows; stage I 40%, stage II 2%, stage III 44%, stage IV 6% and stage V 8%. Favorable histology was diagnosed in 96% and unfavorable histology in 4% of the patients. The National Wilms' Tumor Study strategy were used in the treatment of these cases. Neoadjuvant chemotherapy was given in 34% and all of them received adjuvant chemotherapy. 62% of patients received radiation postoperatively. The 4- year overall survival and Event-free survival were 80% and 60%, respectively. Conclusion As a developing nation, our obtained survival outcome showed a trend of improvement in comparison to other local results reported last decade, but still lower than the treatment outcomes of WT obtained in developed nations. We need more effort to improve our oncology care to get better results. EP-1646 Wilms' Tumor in a war-torn nation: 10-year single institution experience from Iraq

Material and Methods Out of 686 cases of bone metastases, included in the long-term randomized trial in 16 (2,4%) it was impossible to identify the primary tumor site. The most frequent primary site was breast – 62,1%, both prostate and lung tumors were diagnosed in 8,3%, renal in 6,9%, colon in 2,6%. Separately we analyzed the mixed group of 19 patients represented by rare cases of bone metastases of stomach and liver cancer, head and neck tumors, gynecological tumors («Others»). Patient selection criteria for radiotherapy were pain, risk of pathological fracture/malignant spinal cord compression, increasing neurologic dysfunction. Irradiation volume included one anatomical area of the skeleton. Total dose was 13-26Gy in 2-4 fractions of 6,5 Gy. Results The average follow-up period was 70 months. The main characteristics of bone metastases of unknown origin such as gender, age, lesion length, risk of pathological fracture, pain intensity before treatment and effectiveness of EBRT were similar to the bone metastases of colon cancer and to the group «Others». Overall effectiveness of EBRT (сomplete and partial pain relief) for bone metastases of unknown origin was 81,2%, complete response rate attained in 43,8% of cases. Relative pain reduction was 65,4% and turned out to be one of the lowest between analyzed groups. It was significantly lower for bone metastases of unknown origin compared to breast cancer and melanoma (82,7% and 88,9%, р<0,05). Conclusion The results of the study make it possible to classify metastases in the skeleton of unknown origin as radioresistant lesions as well as bone metastases of renal, lung and colon cancer. More in-depth study of gastrointestinal tract in patients with bone metastases of unknown origin is needed. EP-1648 Palliative hipofractionated radiotherapy in non operable rectal cancer: preliminary results. J. Lozano Galan 1 , E. Rubio 1 , J. Solé 1 1 Consorci Sanitari de Terrassa CST, Radiation Oncology Department, Terrassa, Spain Purpose or Objective Many patients with rectal cancer were not candidates for surgical resection because advanced age, comorbidities, or multiple synchronous metastases. In this scenario only comfort measures or different palliative radiotherapy regimens are applied, from single doses to treatments lasting several weeks. The aim of this prospective study is to describe the preliminary results of our protocol of hypofractionated palliative radiotherapy in patients with non-operable rectal cancer. Material and Methods Patients with rectal cancer who were not candidates for surgical resection because advanced age, comorbidities, or multiple synchronous metastases at the time of diagnosis were considered eligible. Patients were immobilized in the prone position with a belly-board in order to reduce small bowel irradiation. To limit organ motion patient were instructed to empty the bladder and drink 500cm3 of water 45-60 minutes before CT simulation and before every treatment fraction. A conformal three-dimensional radiotherapy technique was planned to deliver to the primary tumor and the enlarged pelvic nodes a total dose of 39Gy in 13 sessions of 3Gy in 17 days. Symptomatic response 2 months after the end of treatment has been measured for bleeding and

Electronic Poster: Clinical track: Palliation

EP-1647 Clinical features and efficacy of radiotherapy for bone metastases of unknown origin. N. Bychkova 1 , E. Khmelevsky 1 1 Gertzen Moscow Research Oncological Institute, Radiotherapy department, Moscow, Russian Federation Purpose or Objective The purpose of the current research was to study the efficiency of radiotherapy for bone metastases of unknown origin.