ESTRO 36 Abstract Book

S589 ESTRO 36 _______________________________________________________________________________________________

EP-1071 Organ-sparing SBRT in reirradiation of head and neck cancer: efficacy, toxicity, and quality of life I. Zhang 1 , G. Gill 1 , M. Marrero 1 , A. Sharma 1 , A. Riegel 1 , D. Paul 2 , J. Knisely 1 , S. Teckie 1 , M. Ghaly 1 1 North Shore LIJ Health System, Radiation Medicine, New Hyde Park, USA 2 North Shore LIJ Health System, Medical Oncology, New Hyde Park, USA Purpose or Objective To present a retrospective analysis of the efficacy, toxicity, and quality of life (QOL) of patients treated with organ-at-risk (OAR)-sparing salvage stereotactic body radiotherapy (SBRT) in previously-irradiated head and neck cancer. Material and Methods From November 2012 to July 2015, 60 patients with in- field recurrence of head and neck cancer underwent reirradiation with OAR-sparing SBRT at our institution. OARs were defined as critical structures that had approached their radiation tolerances after prior irradiation and had a high potential to impair QOL if damaged with re-irradiation. Intact tumors were prescribed 40 Gy while 35 Gy was prescribed for post- operative treatments. Doses previously received by the OARs were estimated by deformably registering the prior treatment plan onto the new simulation CT to more accurately delineate dose distributions (Figure 1: Prior plan overlying the new planning CT without (top) and with (bottom) deformable registration). Dose constraints for SBRT were calculated with a biological equivalent dose (BED) using an alpha/beta ratio of 3 to reduce the risk of late toxicities. Treatments were delivered twice a week for a total of 5 fractions via image-guided volumetric arc therapy with the OAR as the fusion surrogate. Quality of life (QOL) data was collected at consultation and follow up using the MD Anderson Dysphagia Inventory (MDADI), Symptom Inventory – Head and Neck Module (MDASI-HN), and Xerostomia Questionnaire. Local control and overall survival were estimated using the Kaplan-Meier method.

Results Sixty patients were treated to 69 sites (9 for a second metachronous failure). Thirty two patients underwent surgical salvage prior to SBRT. Retreatment sites included the aerodigestive tract (43%), lateral neck (22%), and skull base (35%). The median prior radiotherapy dose was 63.6 Gy and the median reirradiation planning target volume (PTV) was 61.0 cm 3 (range 16.8 to 349 cm 3 ). Despite prioritizing OAR-sparing over PTV coverage, the median V90 was 98.4% and D90 was 99.0%. The 1- and 2- year rates of local control were both 54%. Median survival was 18.5 months after SBRT. Late grade 3 toxicities occurred in 3% of the aerodigestive tract group, 1% of the skull base group, and none treated to the lateral neck. No grade 4 or 5 toxicities were observed. Compared to baseline, patients with skull base reirradiation maintained a stable QOL, while patients treated to the aerodigestive tract demonstrated decreased QOL associated with worsening dysphagia. All groups experienced increased xerostomia. Conclusion OAR-sparing SBRT is able to achieve excellent tumor coverage while protecting the organs at highest risk of reirradiation-related complications. Compared to conventional fractionation, the potential for lowered toxicity and maintained QOL makes SBRT a promising salvage option for recurrent head and neck cancer. Further, prioritizing OARs preserves a treatment option for repeat reirradiation in patients who develop a second in- field tumor recurrence. EP-1072 Early nutritional support in head and neck: survey of Italian radiation oncologists/otolaryngologists. M. Trignani 1 , A. Allajbej 1 , A. Di Pilla 1 , M. Nuzzo 1 , S. Di Biase 1 , M. Di Perna 1 , A. Croce 2 , M. Di Nicola 3 , I. Porfilio 3 , D. Genovesi 1 1 Ospedale Clinicizzato S.S. Annunziata, Radiotherapy, Chieti, Italy 2 Otolaryngology, Otolaryngology, Chieti, Italy 3 Preventive Medicine and Hygiene, Biomedical Science, Chieti, Italy Purpose or Objective The aim of this study was to evaluate the most common approaches among Italian radiation oncologists (RO) and otolaryngologists (OL) in early nutritional management of head and neck (H&N) cancer patients. Type of nutritional supplements prophylactically used, timing and criteria of percutaneous endoscopic gastrostomy placement (PEG) and role of nutritional counseling were investigated. Material and Methods A questionnaire, focused on different points of nutritional management in H&N cancer patients, was created and approved by a multidisciplinary team (MDT) including RO, OL and nutritionists. The survey, containing 10 multiple- choice questions, was prepared on SurveyMonkey online interface and emailed to 106 Italian centers of radiation oncology and 100 centers of otolaryngology. Responses were collected over a 2-month period. Descriptive analyses in terms of frequencies and percentages was automatically elaborated by SurveyMonkey. Chi-square test was performed to establish any significant difference between interviewed. Results A total of 67/106 and 27/100 questionnaires sent to Italian centers of Radiation Oncology and Otorhinolaryngology were filled in, corresponding to a response rate of 63.2% and of 27% respectively. Respondents answered all questions, so all were included in the analysis. Regarding nutritional counseling before starting treatment, 53.7% of RO claimed to make it rarely, while 26.9% always; 33.3% of OL affirmed to practice a preventive nutritional counseling rarely, 29.6% always and 22.2% almost always.