ESTRO 2022 - Abstract Book

S915

Abstract book

ESTRO 2022

Mandibular molar sectors of Oropharynx and Oral Cavity tumors were exposed to high Dmean of 40 to 50 Gy, especially when irradiation is bilateral. On the other hand, tooth sectors received lower doses for SH radiation. DERO tool guides post- radiation dental care with a personalized dose map for patients and dentists. With data update and patient follow-up, we will be able to determine ORN risk after head and neck radiation.

PO-1081 BMI and SMI variations in HNSCC patients undergoing radiotherapy and nutritional intervention

F. Mastroleo 1 , C. Pisani 1 , G. Carabelli 1 , A. Collo 2 , M. Garzaro 3 , S. Riso 2 , M. Krengli 1

1 University Hospital Maggiore della Carità, Radiation Oncology, Novara, Italy; 2 University Hospital Maggiore della Carità, Clinical Nutrition and Dietetic, Novara, Italy; 3 University Hospital Maggiore della Carità, ENT, Novara, Italy Purpose or Objective The aim of the study was to analyze the cohort of head and neck squamous cell carcinoma (HNSCC) patients (pts) who underwent radiotherapy (RT) or radiotherapy with concurrent chemotherapy (RT-CHT) and their body mass index (BMI) and skeletal muscle index (SMI) pattern of variation at 3 months after treatment completion. Materials and Methods From 2016 to 2020, we enrolled 73 consecutive HNSCC pts treated by with exclusive or postoperative RT (14 pts) or RT-CHT (59 pts). Pts’ t 0 (at time of diagnosis) and t 3 (3 months after treatment completion) CT scans were retrieved to measure skeletal muscle as cross-section area (CSA) in a single slice at the level of C3 vertebra. Skeletal muscle area was defined as the pixel area between the radiodensity range of -29 and +150 Hounsfield Units (HU) and SMI calculated. Charlson Score was used to assess comorbidities, resulting in a median score of 4 (range: 2-11). Pts were followed-up up to disease progression, relapse or death. Median follow-up was 16 months (range: 3 – 70 months), local-progression-free survival was analyzed. We further analyzed the BMI and SMI variance with variables coming from patients’ clinical data, Mann-Whitney test was used and p-value <0,05 was considered as significative. Results 20 events were recorded: 9 disease progressions and 11 tumor relapses. The 82% of pts was free of progression at 1 year (95% C.I. 0.70-0.89). We analyzed BMI and SMI at t 0 and t 3 . At t 0 , average BMI was 25.79 (SD 4.06), while, at t 3 , it was 24.46 (SD 3.56) with a reduction in 54 pts (73,97%). The difference was evaluated by Wilcoxon signer-rank test, showing a BMI decrease of -1,33 (SD 1.81) and p-value <0.0001. At t 0 , average SMI was 57,14 (SD 11,01), while, at t 3 , it was 59,17 (SD 11,84) with a reduction in 26 pts (35,62%). The difference was evaluated by Wilcoxon signed-rank test, showing a SMI increase of 2,03 (SD 5,47) and p-value <0.0055. BMI and SMI variance did not significantly correlate with analyzed clinical variables. Conclusion The SMI increment found in our population could be justified by the nutritional interventions and supplementation monitored by seriate nutritional follow-up. Furthermore, our study suggests that the assessment of nutritional status by BMI could be potentially insufficient since BMI variations could hide muscle mass variations, impacting in HNSCC prognosis. SMI could represent a more reliable way in muscle mass analysis that could be easily integrated in radiation oncology setting. 1 Mahatma Gandhi Institute of Medical Sciences, Radiotherapy, Wardha, India; 2 Mahatma Gandhi Institute of Medical Sciences , Radiotherapy, Wardha, India; 3 Mahatma Gandhi Institute of Medical sciences , Radiotherapy, Wardha, India; 4 Mahatma Gandhi Institute of Medical , Radiotherapy, Wardha, India; 5 Mahatma Gandhi Institute of medical Sciences , Radiotherapy, Wardha, India; 6 Mahatma Gandhi Institute of Medical Sciences , Radiology, Wardha, India; 7 Mahatma Gandhi Institute of Medical Sciences, Radiology, Wardha, India Purpose or Objective Radiotherapy (RT) forms an integral component of management in head and neck cancers. Accurate delineation of GTV is a key step of RT treatment planning. Target delineation is usually based on contrast enhanced computed tomography (CECT) images and RT doses in IMRT are usually prescribed to GTV of primary (GTVp) and nodes (GTVn). Magnetic resonance imaging (MRI) offers the best soft tissue contrast to define primary tumor and nodes when compared to CECT. As synthetic CECT from the MRI is usually unavailable in RTP (radiotherapy treatment planning systems), RT planning is mostly based on CECT volumes. We therefore, carried out this study to evaluate concordance between CECT and MRI defined target volumes and corresponding dose-volume histogram (DVH) parameters. Materials and Methods 10 consecutive unoperated patients of head and neck cancer were included. All patients underwent CECT for RT simulation. In addition, T1, T2 and T1C MRI images with similar slice thickness as of CECT were obtained. GTVp and GTVn were delineated independently by two radiation oncologists on CECT and MRI images and entire sets of contours. These were reviewed jointly by another group of two radiation oncologists and radiologist. GTVp and GTVn were included in high-risk volume, adjacent nodal levels were taken in intermediate-risk volumes, while prophylactic nodal levels were included in low-risk volume. Corresponding PTVs were generated and IMRT planning was done. Three dose levels of 70 Gy, 63 Gy, 56 PO-1082 CECT vs. MRI: Impact of concordance index for gross target volume in IMRT of head and neck cancers P. Kalbande 1 , B. Mahindrakar Jain 2 , A. Singh 3 , N. Shanmugam 4 , P. Kale 5 , Z. Mathi 1 , B. Borikar 6 , A. Tayde 7 , N.R. Datta 2