ESTRO 2020 Abstract book

S11 ESTRO 2020

loss under treatment, enteral feeding by tube was proposed. Complete treatment was defined as full planned RT doses without more than 3 days interruption, and full planned doses of cisplatin and cetuximab if indicated. Sarcopenia was determined by measure of skeletal muscles at the third lumbar vertebra on the planning CT-scan of radiotherapy. Sarcopenia was defined as SMI (Skeletal muscle index) less than 52.4cm²/m² for men and 38.5cm²/m² for women. Results Among the 257 HNSCC patients included, 120 (47%) were treated by RT and 137 (53%) by RTCT. The mean age was 60.8 years with 196 men (76%) and 61 (24%) women. Before radiotherapy, 94 (37%) patients were sarcopenic. Sarcopenia was more frequent among men (40.7%) than women (25%) (p=0.04). 65 patients (25%) did not complete treatment, all but 3 in the RTCT group. Median weight lost was higher among patients who did not complete treatment (7 vs 4.3 kg, p<0.0001), as well as patients with grade 3 toxicities (53 vs 34%, p=0.012). At 18 months, overall survival (OS) was 75% in sarcopenic patients vs 86% in non-sarcopenic patients (p=0.0002). Progression free survival (PFS) was also decreased in case of sarcopenia (61 vs 80%, p<0.0001). The poor prognostic value of sarcopenia at 18 months OS was observed among patients treated by RTCT (79% vs 87%, p=0.01) or by RT (72% vs 84%, p=0.009). PFS was also decreased in case of sarcopenia for patients treated by RTCT (68% vs 79%, p=0.01) or by RT (54% vs 80%, This study confirms that pretherapeutic sarcopenia is very frequent and can predict OS and PFS in patients treated with RTCT or RT for HNSCC. Specific management of this at-risk population is therefore essential. PH-0040 A 6-point scale approach to 18F-FDG PET-CT for response assessment in HNSCC: a multicenter study P. Bonomo 1 , A. Merlotti 2 , S. Morbelli 3 , V. Berti 4 , C. Saieva 5 , F. Bergesio 6 , A. Bacigalupo 7 , L. Belgioia 7 , C. Franzese 8 , E. Lopci 9 , A. Casolo 10 , E. D'Angelo 11 , D. Alterio 12 , L. Travaini 13 , L. Berretta 14 , V. Pirro 15 , S. Ursino 16 , D. Volterrani 17 , M. Roncali 18 , F. Vigo 19 , I. Desideri 1 , E. Russi 2 , L. Livi 1 , A. Bianchi 20 1 Azienda Ospedaliero-Universitaria Careggi, Radiation Oncology, Florence, Italy ; 2 Azienda Ospedaliera S.Croce e Carle, Radiation Oncology, Cuneo, Italy ; 3 IRCCS Ospedale Policlinico San Martino, Nuclear Medicine, Genoa, Italy ; 4 Azienda Ospedaliero-Universitaria Careggi, Nuclear Medicine, Florence, Italy ; 5 Institute for cancer research- prevention and clinical network ISPRO, Cancer Risk Factors and Lifestyle Epidemiology Unit, Florence, Italy ; 6 Azienda Ospedaliera S.Croce e Carle, Medical Physics, Cuneo, Italy ; 7 IRCCS Ospedale Policlinico San Martino, Radiation Oncology, Genoa, Italy ; 8 Humanitas Clinical and Research Hospital - IRCSS, Radiotherapy and Radiosurgery, Rozzano- Milan, Italy ; 9 Humanitas Clinical and Research Hospital - IRCSS, Nuclear Medicine, Rozzano- Milan, Italy ; 10 University Hospital, Nuclear Medicine, Modena, Italy ; 11 University Hospital, Radiation Oncology, Modena, Italy ; 12 IEO European Institute of Oncology IRCCS, Radiation Oncology, Milan, Italy ; 13 IEO European Institute of Oncology IRCCS, Nuclear Medicine, Milan, Italy ; 14 Azienda Ospedaliera SS Antonio e Biagio e C.Arrigo, Radiation Oncology, Alessandria, Italy ; 15 Azienda Ospedaliera SS Antonio e Biagio e C.Arrigo, Nuclear Medicine, Alessandria, Italy ; 16 Azienda Ospedaliero- Universitaria Pisana, Radiation Oncology, Pisa, Italy ; 17 Azienda Ospedaliero-Universitaria Pisana, Nuclear Medicine, Pisa, Italy ; 18 Azienda USL - IRCCS, Nuclear Medicine, Reggio Emilia, Italy ; 19 Azienda USL - IRCCS, Radiation Oncology, Reggio Emilia, Italy ; 20 Azienda Ospedaliera S.Croce e Carle, Nuclear Medicine, Cuneo, Italy p=0.0008). Conclusion

Purpose or Objective Response assessment after definitive radio-chemotherapy (RCT) for HNSCC is based on a 12-week FDG PET-CT. The 5-point Hopkins score (HS) is the only qualitative scale available for standardized reporting, albeit limited by suboptimal positive predictive value (PPV). The aim of our study was to explore the feasibility and assess the diagnostic accuracy of an experimental 6-point scale (“Xxxxx score” from the name of the city where the scale was designed) Material and Methods Patients with locally advanced HNSCC undergoing RCT between 1/10 and 12/15 could be enrolled. Baseline and post-treatment PET-CT scans had to be available for each subject. The post-treatment scan had to be executed not before 10 weeks and no later than 6 months after RT completion.An indipendent qualitative evaluation of post- treatment scans was undertaken by 3 experienced nuclear medicine physicians who were blinded to patients’ information, clinical data and other imaging examinations. Response to treatment was evaluated according to HS and Xxxxx score (table 1).The primary endpoint of the study was to evaluate the PPV of Xxxxx score in assessing locoregional control (LRC). We also correlated semi- quantitative metabolic factors as included in PERCIST and EORTC criteria with disease outcome. Based on a PPV of HS of 71.1% (Marcus et al, J NucI Med 2014), applying the experimental 6-point score was hypothesized to yield a 20% increase. With a significance level α=0.05 and a power of 0.90 when the PPV is 85.3%, the required sample size with this design was 81 patients