ESTRO 37 Abstract book

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ESTRO 37

3 European Institute of Oncology, Epidemiology and Biostatistics Unit, Milano, Italy 4 Centro Nazionale di Adroterapia Oncologica CNAO, Medical Physics Unit, Pavia, Italy 5 University of Turin, Department of Oncology- Radiation Oncology, Turin, Italy 6 University of Piemonte Orientale, Radiotherapy Unit, Novara, Italy 7 European Institute of Oncology, Unit of Medical Physics, Milano, Italy 8 Centro Nazionale di Adroterapia Oncologica CNAO, Scientific Directorate, Pavia, Italy 9 European Institute of Oncology, Scientific Directorate, Milano, Italy Purpose or Objective We prospectively evaluated a cohort of patients (pts) with locally advanced (T3-T4, N0-N3, M0) nasopharyngeal carcinoma (LANPC) treated using a sequential mixed beam (MB) approach (Intensity Modulated Radiotherapy - IMRT- followed by proton therapy boost). Clinical outcomes and radiation-related acute and late toxicity were analyzed. Moreover, a retrospective analysis of LANPC pts, treated with only IMRT, was performed and results were compared to those obtained in the MB group. Material and Methods Seventeen consecutive pts with LANPC treated with MB approach (between July 2012 and May 2017) were evaluated. First phase of treatment consisted in IMRT up to a total dose of 54-60 Gy (elective irradiation of the neck and macroscopic disease) performed at the patients’ reference center. Second phase consisted in proton therapy boost on the pre-treatment macroscopic disease (performed with pencil beam scanning, up to a total dose of 70-74 Gy RBE -Relative Biological Effectiveness). Seventeen pts with LANPC treated with only IMRT (up to a total dose of 70 Gy, 2-2.12 Gy/die, Simultaneous Integrated Boost technique) between November 2006 and February 2015 were also analyzed. For both groups of pts, response to treatment was assessed at 6 months from the end of treatment. Clinical outcome (local control -LC-, 3-year local relapse free- - LRFS-, distant metastases free- survival -DMFS-) and toxicity profile were evaluated. For the purpose of the study the response to treatment, LC and LRFS was considered only for the primary tumor in the nasopharynx Results Patient, tumor and treatment characteristics of bothgroups were summarized in Tab. 1. An example of accumulated doses of the MB approach (IMRT and proton therapy) was represented in Fig 1 Pts treated with IMB and IMRT had a median follow-up of 31 and 51 months, respectively. LC, 3-year LRFS and DMFS were 93%,93%,64% and 81%,85% and 81% for MB and IMRT group, respectively. Although cT4 represented 71% and 41% of cases in MB and IMRT cohort of pts, LC control was not statistically different between the two groups (p=0.60). No G4 acute and late toxicity was found. The most frequent acute toxicities were: G2-G3 mucositis and dysphagia found in 71%, 88% and 53%, 53% in MB and IMRT group, respectively. Grade 2-3 late xerostomia was found in 33% and 19% for MB and IMRT group, respectively. Long term endocrine disorders were found in 7% and 6% of pts treated with MB and IMRT, respectively. Finally, although a significant higher total dose was prescribed to pts treated with a MB approach (p=0.02) the toxicity profile were similar between the two groups.

evaluation seventeen patients (51.5%) exhibited no residual disease and two patients presented minimal residual disease after treatment. Laryngectomy-free survival at 2 years and at 5 years was 82.9% and 76.4% respectively. PFS at 5 years was 63.5% in patients with pathological complete response and 31.7% if persistent disease (p=0.16). Salvage surgery didn’t improve loco- regional control compared with chemoradiation alone and higher rates of distant metastasis were observed in the surgery arm: 35.5% vs. 13% (p=0.004). Conclusion Persistent disease after organ preservation treatment is related with poor prognosis and high risk of distant failure. Therefore, selection of patients who may benefit from surgery is of upmost importance. EP-1114 Organ-sparing treatment in locally advanced head and neck carcinoma. J.A. Dominguez Rullan 1 , A. Hervás Morón 1 , M. Vallejo Ocaña 1 , M. Martín Martín 1 , R. Morís 2 , D. Sevillano 2 , S. Sancho García 1 1 Hospital Universitario Ramón y Cajal, Radiation Oncology, Madrid, Spain 2 Hospital Universitario Ramón y Cajal, Medical Physics, Madrid, Spain Purpose or Objective To report the acute toxicity profile and outcome of concurrent radiotherapy and chemotherapy for organ preservation in locally advanced head and neck cancer. Material and Methods 187 patients were treated with chemoradiation with radical intent over a 12-year period. Twenty-five patients treated into clinical trials or without concomitant chemotherapy were excluded from analysis. Overall survival (OS), cancer-specific survival (CSS) and progression-free survival (PFS) were calculated using the Kaplan-Meier and the logrank-test was used to analyse the following predictors: age, sex, primary tumor location and chemotherapy scheme. Results Mean age at diagnosis was 61 years (range 40-87), being 85.7% males. 24.2% of patients were stage III and 75.8% stage IV. Tumor locations included: 75 oropharynx (46.6%), 57 larynx (35.4%), 28 hypopharynx (17.4%) and one oral cavity (0.6%). Mean dose was 50 Gy to clinical target volume (CTV) and 70 Gy to gross target volume (GTV). The chemotherapy regimens used were weekly cisplatin (66.5%), three-weekly cisplatin (16.1%), carboplatin (9.3%) and cetuximab (6.8%). Grade 3-4 mucositis was seen in 29.2% of patients, grade 3 epithelitis in 8.7% of patients and grade 3-4 neutropenia in 11.1% of patients. Median follow-up was 30 months (range 2-157). At 2 and 5 years OS was 66.8% and 45.1%; CSS 76.8% and 66.7%; and PFS 69.9% and 61.8%, respectively. The larynx location and weekly cisplatin chemotherapy regimen were significant predictors of longer OS and CSS (p<0.05) in univariate analysis. Conclusion Organ preservation treatment in locally advanced head and neck carcinoma provides good survival results and toxicity profile, comparable to those published in the literature. EP-1115 Local control for T3-T4 nasopharyngeal cancer treated with mixed beam (photons-protons) radiotherapy D. Alterio 1 , E. D'Ippolito 2 , P. Fossati 2 , R. Ricotti 1 , S. Gandini 3 , V. Barbara 2 , V. Vitolo 2 , M. Bonora 2 , E. Mastella 4 , G. Magro 4 , P. Franco 5 , M. Krengli 6 , S. Comi 7 , F. Valvo 2 , B. Jereczek-Fossa 1 , R. Orecchia 8,9 1 European Institute of Oncology, Radiation therapy Unit, Milano, Italy 2 Centro Nazionale di Adroterapia Oncologica CNAO, Radiation therapy Unit, Pavia, Italy