ESTRO 2020 Abstract book

S502 ESTRO 2020

radiotherapy (CCR) through the EORTC QOL C30 quality of life questionnaire. Material and Methods A prospective study of 27 patients treated with CCR for NPC between October 2017 and July 2018. Median age was 43.5 years [26-65] with a sex ratio of 1.7. All patients received first-line chemotherapy. CCR consist on intensity modulated radiotherapy (IMRT) at a dose of 69.96 Gy in 33 daily fractions with weekly cisplatin (40mg/m²) chemotherapy. During the treatment period, patients completed the EORTC QOL C30 (adapted for Tunisia) questionnaires weekly. In this study we had only evaluate the overall health and QOL rating: Q29 How would you rate your overall health during the past week? (1-7) ; Q30 : How would you rate your overall quality of life during the past week? (1-7). Paired-Samples T test was used to compare mean scores: between the first Day (FD) and mid treatment (MT) ; the FD and the last day (LD) of treatment. p < 0.05 was considered statistically significant. Results The Mean overall health rating was 5.5 ± 1.7 ; 4.8 ± 1.4 and 4.3 ± 1.7 respectively at FD, MT and LD. The difference was statistically significant between FD and LD (p=0.008) but not between FD and MT (p=0.08). The Mean overall QOL rating was 5.4 ± 1.5 ; 4.8 ± 1.5 and 4.2 ± 1.7 respectively at FD, MT and LD. The same results of comparison were noticed for QOL : p(FD/MT)=0.1 and p(FD/LD)=0.006. Conclusion In the literature, QOL assessment is generally lacking and is often relevant to late toxicities only. However, as shown by the results of our study, the initial phase of treatment is also responsible for a significant deterioration in the QOL of patients that must be considered. PO-0848 Study of anatomical change during H&N RT with effect on delivered dose to spinal cord, parotid gland A. Srivastava 1 , R. Rathod 1 , K. Talapatra 1 , A. Sharma 1 , V. Mhatre 1 , P. Chadha 1 , M. Deshpande 1 , R. Mistry 1 , I. Shaikh 1 , S. Limaye 1 , S. Goyle 1 1 Kokilaben Dhirubhai Ambani Hospital, Radiation Oncology, Mumbai, India Purpose or Objective The impact of weight loss and anatomical changes during head and neck radiotherapy on spinal cord dosimetry is poorly understood, limiting evidence-based adaptive management strategies. Aim of the study is to calculate the difference in planned and observed dose to Organs at Risk (OARs) like spinal cord and parotid gland contoured and planned in a sequential periodically acquired on board Kilo voltage Cone Beam CT (kVCBCT). This studie's purpose is to study anatomical changes during head and neck radiation treatment and its effect on delivered dose to spinal cord, parotid gland and PTV Material and Methods A cohort of 14 patients were retrospectively analyzed with a minimum prescribed dose of 60 Gray in 30 fractions, and availability of daily kVCBCT images for dose recalculation. Bilateral parotids, spinal cord, and PTV were contoured on kVCBCT of day 8, day 16, day 24, day 30 and separate plans were created and a dosimetric analysis was done for the same. Unpaired t test was used to analyze the results. Results Average of delivered dose to spinal cord in these patients, for 8 th fraction was 2.73%, for 16 th fraction 5.553%, for 24 th fraction 4.40% and for last fraction 3.83% higher than prescribed dose (p<0.005). Average of mean delivered dose per patient for all fractions is also lower than prescribed dose almost for all patients for both parotids. Average of mean delivered dose to PTV in these patients, for 8 th fraction is 0.03%, for 16 th fraction 0.67%, for 24 th fraction 1.20% and for last fraction 1.43% lower than prescribed dose (p<0.005).

PO-0846 Preliminary outcome results of a PET-CT based direct planning protocol in head and neck radiotherapy S. Di Biase 1 , F. Perrotti 1 , G. Pavanato 1 , G. Montesi 1 , G. Virdis 1 , A. Ferretti 2 , E. Bellan 2 , L. Rampin 3 , M. Maffione 3 , G. Mandoliti 1 1 Santa Maria della Misericordia Hospital, Radiotherapy department, Rovigo, Italy ; 2 Santa Maria della Misericordia Hospital, Medical Physics department, Rovigo, Italy ; 3 Santa Maria della Misericordia Hospital, Nuclear Medicine department, Rovigo, Italy Purpose or Objective We report treatment planning implications and early clinical outcome of a simulation PET-CT (sPET-CT) and direct planning protocol in head and neck (H&N) cancer radiotherapy (RT). Material and Methods Twenty-two consecutive H&N cancer patients underwent to an optimized procedure of sPET-CT in RT set-up (flat top, mould), using a specific PET acquisition protocol (2 beds, matrix 400x400, 6 minutes/bed). Gross tumor volume (GTV) was delineated using an automated threshold method at 50% of the intralesional SUV max. Clinical target volume (CTV) was obtained adding a 9-mm isotropic margin, respecting anatomical boundaries. A 3- mm margin was added to generate the planning target volume (PTV). Volumetric modulated arc therapy (VMAT) plans were designed by including also elective nodal stations as indicated. To assess early clinical outcome the first evaluation, with PET-CT and/or CT plus clinical examination, was performed 2 months after RT, then every 3 months. Results All 22 enrolled patients showed GTV evidence on PET-CT at baseline. Subsites involved were: oral cavity (5), oropharynx (7), larynx (7), hypopharynx (1), nasopharynx (1) and ethmoid sinus (1). The stage of disease ranged widely. Dose prescription ranged from 66 to 70 Gy, with SIB. Concurrent chemotherapy was administered in 17/22 patients. All patients completed RT. A two months follow- up evaluation was performed for 21 patients. Fifteen/21 patients showed a complete response at PET-CT and/or CT plus clinical examination, 5/21 showed a partial response and 1 patient had disease progression. After a 7 months mean follow-up 16 patients were evaluable. Ten patients were confirmed with a complete response and 1 patient with partial response. One patient experienced a complete response after partial response. In the 3 remaining cases we observed a disease progression. Conclusion In our cohort, sPET-CT could be considered an optimization in RT planning. H&N patients undergone to sPET-CT direct planning protocol showed good early responses to treatment. Longer follow up, larger and more homogeneous series of patients are needed to confirm these data. PO-0847 Quality of life during chemo-radiotherapy for nasopharyngeal carcinoma: A prospective assessment N. Fourati 1 , Z. Fessi 1 , O. Nouri 1 , F. Dhouib 1 , W. Siala 1 , W. Ben Kridis 2 , A. Khanfir 2 , W. Mnejja 1 , J. Daoud 1 1 Faculté de médecine Université de Sfax, Radiotherapy Department Habib Bourguiba Hospital, Sfax, Tunisia ; 2 Faculté de médecine Université de Sfax, Medical Oncology Habib Bourguiba Hospital, Sfax, Tunisia Purpose or Objective Quality of life (QOL) is an important treatment outcome in nasopharyngeal carcinomas (NPC). Several rating scales are available to assess the importance of symptoms and the QOL of cancer patients. The aim of our study was to evaluate the evolution of overall health and QOL rating during concurrent chemo-