ESTRO 38 Abstract book

S657 ESTRO 38

reported in head and neck cancer patients treated with transoral laser microsurgery (TLM) rather than open procedures. We sought to characterize patient reported quality of life outcomes in patients treated with TLM and HPV positive oropharyngeal squamous cell carcinoma patients treated at a single institution from February 2013 through March 2015 were included in the study. The patients prospectively completed the University of Washington Head and Neck Quality of Life Surveys (UW- QOL) at baseline and every 3 months after therapy. The UW-QOL survey evaluated QOL in 12 domains specific to head and neck cancer and 3 domains of global health status, assigning scores on 0-100 scale. Initial analysis was conducted utilizing repeated measures mixed models, with underlying unstructured covariance, utilizing all survey data to determine if significant differences existed in QOL over time for each of the 15 scored questions. Comparisons between paired time- points was conducted via T-tests utilizing Tukey’s adjustment for multiple comparisons. Similarly, univariate mixed models were fit utilizing clinical and demographic variables in order to determine their association with QOL outcomes with statistical significance considered for p < 0.05. Kaplan-Meier methods estimated Locoregional control, distant control and overall survival. Results Of the 26 patients participating, 25 of the patients completed at least two of the assigned surveys and are included in this analysis. Forty-four percent received concurrent chemotherapy. Median follow up was 44 months, with the respective 1-year and 2-year LRC, DC, and OS of 100%/100%, 100%/87%, and 96%/96%. Within 9 months after IMRT, 100% of patients QOL scores were not significantly worse than pre-treatment for all QOL questions. Saliva quantity and consistency was the only question in which QOL was significantly lower than baseline at any time-point, however, within 9 months patients had recovered to within a non-significant statistical and clinical difference. The average measures of Pain, Recreation, Mood, Anxiety, health-related QOL, and overall QOL were all significantly higher for all patients at 12 months than baseline, with Mood and Anxiety achieving significant improvement at 6and 9 months, respectively. Mixed Modelling identified worse QOL associated with primary base of tongue treatment, bilateral neck surgery, advanced pathological T Stage, no PNI, higher dose, and a distant recurrence needing salvage treatment (p < 0.05). Conclusion QOL for HPV positive oropharyngeal carcinoma after TLM and IMRT returns to pre-RT levels within 9 months of treatment, with most patients achieving a clinically significant increase in QOL within 12 months of treatment. This treatment approach appears to provide excellent disease control while preserving their quality of life. EP-1186 The new target delineation impact on carotid and bulb sparing for T1 glottic cancer: VMAT vs 3DCRT L. Ferella 1 , F. Vittorini 2 , E. Varrassi 3 , P. Franzese 3 , M. Di Staso 3 , F. Marampon 4 , C. Sorce 5 , A. Chalaszczyk 5 , G. Grimaldi 5 , E. Di Cesare 6 , E. Orlandi 7 , V. Tombolini 4 , C. Masciocchi 8 , G.L. Gravina 5 1 Fondazione IRCC Istituto Nazionale dei Tumori Milan- University of L'Aquila, Radiotherapy 2 Unit. Department of Biotechnological and Applied Clinical Sciences- Division of Radiotherapy. Laboratory of Radiobiology L'Aquila, Milano, Italy ; 2 San Salvatore Hospital, Service of Medical Physics., L'Aquila, Italy ; 3 San Salvatore Hospital- University of L'Aquila, Department of Radiation Oncology, L'Aquila, Italy ; 4 Policlinico Umberto I Hospital- Sapienza- University of Rome, Department of Radiation Oncology, Rome, Italy ; 5 University of L'Aquila, Department of Biotechnological and Applied Clinical Sciences- Division of Radiotherapy. Laboratory of adjuvant radiotherapy. Material and Methods

Radiobiology, L'Aquila, Italy ; 6 University of L'Aquila, Department of Biotechnological and Applied Clinical Sciences- Division of Radiotherapy., L'Aquila, Italy ; 7 Fondazione IRCCS Istituto Nazionale dei Tumori, Radiotherapy 2 Unit- Radiotherapy 1 Unit, Milano, Italy ; 8 University of L'Aquila, Department of Biotechnology & Applied Clinical Science., L'Aquila, Italy Purpose or Objective To investigate whether Volumetric Modulated Arc Therapy (VMAT) maintains its superiority on 3D-conformal- radiotherapy (3DCRT) in reducing dose to carotid arteries (CA) and carotid bulbs (CB) using a target sparing contouring approach in cT1 glottic cancer (GC). Material and Methods CTV of 10 cT1aN0 GC patients were retrospectively contoured according to the new contouring recommendations proposed by Gregoire and colleagues. The CAs were separately outlined along their extracranial course. Since CB is the most critical structure involved in atherosclerosis, it was also outlined including two cm superior and inferior to carotid bifurcation according to Framingham Heart study. A 1 mm isotropic margin was applied to account for anatomical changes during cardiac cycle. 3DCRT and VMAT plans specifically optimized for carotid sparing were generated. The prescribed dose was 63 Gy in 28 fractions. In all plans at least 95% of the PTV was requested to receive ≥95% of the prescription dose and a spinal cord maximum dose of 25 Gy was allowed. Ipsilateral and contralateral CB and CA Dmax, Dmean, V35, V50 were determined. The two techniques were also compared for OAR doses and plan quality indices (V95, V107, D2, D98, Conformity index and Heterogeneity Index). T test for paired data with logarithmic transformation for continuous variables was used to compare dosimetric parameters. Mean and confidence interval of 95% were used to summarize continuous variables. A Two-sided α error of 5% was used as significance threshold. Results Mean ipsilateral CB and CA Dmax significantly decreased from 51,8 Gy to 32,8 Gy (p<0.0001) and from 54 Gy to 44 Gy (p=0,0005) for 3DCRT and VMAT, respectively. VMAT significantly lowered ipsilateral CB Dmean (p=0,0001) and V35 (p=0,0052) and ipsilateral CA V35 (p=0,0002). Similarly, contralateral CB (p<0,0001) and CA Dmax (p<0,0001) were lower in Vmat than in 3DCRT. Moreover, contralateral CB (p=0,0002) and CA Dmean (p<0,0001) and contralateral CB (p=0,02) and CA V35 (p=0,0052) were higher with 3DCRT. VMAT significantly reduced the dose to pharyngeal constrictor muscles, thyroid gland and supraglottic larynx. Spinal cord Dmax was lower in 3DCRT plans (Table 1). No significant difference was found in terms of plan quality indices except for the better Conformity Index of VMAT plans (0,7 vs 0,6 of 3DCRT, p=0,0197). As regards hot-spots volumes, no sensitive structures out of target volumes such as contralateral arytenoids were involved. For both VMAT and 3DCRT hot- spots fell insight the PTV. In particular, ipsilateral arytenoid was involved in the 30% of 3DCRT and in 40% of VMAT plans, while ipsilateral supraglottic space in the 20% of 3DCRT and in 20% of VMAT plans.