ESTRO 2020 Abstract book

S487 ESTRO 2020

preservation (Good prognostic 75%; Intermediate Prognostic 59%; Poor Prognostic 30%). Conclusion We can conclude that TALK prognostic model for predicting larynx preservation outcome is nowadays a good tool to help clinicians to take decisions in order to decide which patients should avoid laryngeal preservation schemes and perfume directly a laryngectomy at time of diagnosis in our population. PO-0816 Organs at Risk in Re-Irradiation of Head and Neck Cancer: An Individual Risk-Benefit Tradeoff T. Held 1 , S.B. Harrabi 1 , K. Lang 1 , S. Akbaba 1 , P. Windisch 2 , D. Bernhardt 1 , S. Rieken 1 , K. Herfarth 1 , J. Debus 1 , S. Adeberg 1 1 Heidelberg University Hospital, Department of Radiation Oncology, Heidelberg, Germany ; 2 University Hospital of Zurich, Department of Radiation Oncology, Zurich, Switzerland Purpose or Objective Carbon ion re‐irradiation (CIR) was evaluated to investigate treatment planning and the consequences of individual risk‐benefit evaluations concerning dose‐ limiting organs at risk (OAR). Material and Methods A total of 115 consecutive patients with recurrent head and neck cancer (HNC) were after initial radiotherapy and CIR at the same anatomical site. Tumor infiltration of the base of the skull or the immediate surroundings occurred in 94 patients (n = 94, 81.7%). The cumulative dose applied to OAR such as the optic system was determined for each patient. Toxicities were evaluated in line with the Common Terminology Criteria for Adverse Events 4.03. Results The median interval between the previous course of irradiation and CIR was 3.4 years (range 0.3–13.3 years). A median total dose of 51 Gy relative biological effectiveness (RBE) (range 39–60 Gy (RBE)) in fractions of 3 Gy (RBE) was applied. The median planning target volume (PTV) and clinical target volume (CTV) were 128.9 cc (range 13.3–925.0 cc) and 83.1 (range 6.3–710.5 cc), respectively. No simultaneous systemic therapy was applied during CIR. The median maximum cumulative equivalent doses applied in fractions of 2 Gy (EQD2) to the brainstem, optic chiasm, ipsilateral optic nerve, and spinal cord were 56.8 Gy (range 0.94–103.9), 51.4 Gy (range 0– 120.3 Gy), 63.6 Gy (range 0–146.1 Gy), and 30.1 Gy (range 0.2–87.7 Gy), respectively. In 49 patients (n = 49, 42.6%), the orbital cavity was infiltrated by the tumor. When these cases were excluded (n = 66 patients, 57.4%), the maximum cumulative EQD2 applied to the ipsilateral optic nerve and the optic chiasm was 42.4 Gy (range 0–102.7 Gy) and 27.4 Gy (range 0–93.6 Gy), respectively. The total maximum dose of CIR applied to the brainstem, optic nerve, and spinal cord was 20% higher if the radiotherapy interval was more than two years. The median follow up after CIR was 24.0 months (range 2.5–72.0 months). The cumulative rates of acute and late severe (≥ grade III) side effects after CIR were 1.8% and 8.7%, respectively. Conclusion In recurrent HNC, an individual risk‐benefit tradeoff is frequently inevitable due to unfavorable location of tumors near OAR. There are uncertainties about the dose tolerance of OAR after CIR, which warrant increased awareness about the potential treatment toxicity and further studies on heavy ion re‐irradiation.

findings, type D and type AD tumors peaked at 30‐36 and 18‐24 months after initial treatment,respectively, followed by a long‐term obvious downward trend.Notably,the mortality of type D and type AD patients in the first 3 years after metastasis was extraordinarily higher than that of type A tumors. For type A and type AD tumors recurrence, two different peaks occurred within the first 5 years after initial treatment. Conclusion In non‐endemic area,metastases and recurrence patterns differed across tumor types. The type AD tumors has the worst OS and the clinical process is more radical,and the peak of metastasis and recurrence occurred simultaneously within 5 years after the initial treatment.The type AD and type D tumors have higher metastasis rate and poorer prognosis after metastasis compared to type A tumors. The patients of type A and type AD are more likely to recur than type D NPC. PO-0815 Validation of a Prognostic Model for Predicting Larynx Preservation Outcome in Catalan Population. J. Marruecos Querol 1 , J. Rubió‐Casadevall 2 , A. Lozano 3 , M. Buxó 4 , I. Linares 3 , I. Planas 5 , J. Vayreda 1 , B. Cirauqui 6 , M. Taberna 7 , V. Quiroga 6 , M. Tobed 8 , T. Bores 8 , M. Saigi 3 , E. Felip 6 , S. Recalde 9 , A. Eraso 1 , R. Mesia 6 1 Institut Català d'Oncologia, Radiation Oncology, Girona, Spain ; 2 Institut Català d'Oncologia, Medical Oncology, Girona, Spain ; 3 Institut Català d'Oncologia, Radiation Oncology, Hospitalet de Llobregat, Spain ; 4 Institut d'Investigació Biomèdica de Girona IDIBGI, Statistic Department, Girona, Spain ; 5 Institut Català d'Oncologia, Radiation Oncology, Badalona, Spain ; 6 Institut Català d'Oncologia, Medical Oncology, Badalona, Spain ; 7 Institut Català d'Oncologia, Medical Oncology, Hospitalet de Llobregat, Spain ; 8 Hospital Trueta, Otorhinolaryngology, Girona, Spain ; 9 Institut Català d'Oncologia, Radiation Oncology, Hospitalet Llobregat, Spain Purpose or Objective Total laryngectomy (TL) with adjuvant radiotherapy (RT) was the treatment of choice in patients with locally advanced laryngeal/hypopharyngeal (LALH) tumors. Many efforts have been made to preserve this organ through treatments based on chemotherapy (CT) and RT without compromising overall survival (OS), but improving quality of life, though not all patients respond in the same way. Sherman et al. (Laryngoscope 122, May 2012) validated a prognostic model based on 4 variables (staging T, albumin level, consumption of liquor and KPS) called TALK model, to establish 4 prognostic subgroups (TALK 0 ‐ good prognostic; TALK 1 or 2 ‐ Intermediate prognostic; TALK 3 or 4 ‐ poor prognostic) for laryngeal preservation, in 170 patients with LALH tumors from 1988‐1995, in order to define which subtype of patients would or not be eligible to perform a preservation treatment with CT/RT instead of TL at time of diagnosis with good prognosis Material and Methods Our series retrospectively evaluated 175 patients diagnosed with LALH carcinoma treated with a laryngeal preservation scheme with induction CT and radical CT/RT between 2008 and 2015. TALK score model was applied in all our patients, and prognostic subgroups were generated in order to reproduce the original results. Results Male/female ratio 96.6% / 3.4%. Location was 66.3% larynx; 33.7% Hypopharynx. Stage III 37.7% and Stage IV 62.3%. Smokers 98.3%. Alcohol users 77.1%. 85% of patients achieved larynx preservation at the end of treatment. Overall laryngectomy free survival at 36 months was 84.6%. Overall survival (OS) at 36 months was 68%. Patients were classified in three TALK prognostic subgroups (Good prognostic 40%; Intermediate Risk 53% and Poor prognostic 7%). TALK score was predictor of OS at 36 months (Good prognostic 82%; Intermediate Risk 63% and Poor Prognostic 33%) and it was also predictor of larynx