ESTRO 38 Abstract book

S641 ESTRO 38

terms of survival outcomes. The higher rates of some toxicities and the higher rates of treatment interruptions in the w group could be explained by the worse patients and disease characteristics at baseline. A prospective randomised study comparing these two schedules is desirable to define the optimal chemotherapy association for patients treated with radical intent. EP-1157 Elective nodal dose of 40 Gy is sufficient for locally advanced oropharyngeal carcinoma. K. Asai 1 , S. Ohga 1 , S. Nomoto 1 , T. Yoshitake 1 , M. Shinoto 1 , K. Matsumoto 1 , H. Hirata 1 1 Kyushu University, Clinical Radiology, Fukuoka, Japan Purpose or Objective To clarify the optimal dose of elective nodal irradiation for locally advanced oropharyngeal squamous cell carcinoma. Material and Methods We enrolled 119 locally advanced oropharyngeal carcinoma patients treated at our institusion between April 2003 and October 2017. The inclusion criteria were followings: 1) over 6 months of follow-up period, 2) treated with definitive chemoradiotherapy or bioradiotherapy. In our institution, elective nodal regions were received 40 - 41.4 Gy with fraction size of 1.8 - 2 Gy. Gross lesions were tprescribed with 65 – 70 Gy. We evaluate the pattern of failure, overall survival rate, and progression free survival rate. Incidence of regional failure within the elective nodal region is also evaluated. Results The median age of the patients was 63 years old, and the median follow up period was 44 months. Clinical Stage (according to AJCC 7th) was Stage Ⅲ in 21, Stage Ⅳ a in 86, Stage Ⅳ B in 12. HPV status was p16 positive in 21, negative in 15, unknown in 83. Smoking status was ≥10 pack-years in 79, <10 pack-years in 35, unknown in 5. Treated with cheoradiotherapy in 115, bioradiotherapy in 4. Treatment method was 3D-CRT in 99, IMRT in 20. Recurrence was observed in 39 cases. The 5-year Overall survival rate and progression free survival rate was 76.6% and 63.2%, respectively. The pattern of failure was local in 21, regional in 17, distant in 11. Among the regional recurrence cases, nodal recurrence within the elective nodal regions was observed only in one case. Conclusion Dose of 40 Gy is sufficient for elective nodal region in locally advanced oropharyngeal cancer. EP-1158 Impact of postoperative target volumes in management of head and neck carcinoma of unknown primary F. Podeur 1 , P. Pommier 2 , J. Ton Van 3 , E. Monchet 3 , D. Girodet 1 , M. Poupart 1 , P.E. Roux 1 , P. Zrounba 1 , M. Julieron 3 , S. Deneuve 1 1 Centre Léon Bérard, Head and Neck, LYON, France ; 2 Centre Léon Bérard, Radiotherapy, Lyon, France ; 3 Centre Oscar Lambret, Head and Neck, Lille, France Purpose or Objective We aimed to compare the outcomes of postoperative unilateral radiotherapy (UL-RT) versus bilateral radiotherapy plus total mucosal irradiation (COMP-RT) in management of head and neck carcinoma of unknown primary (HNCUP). Material and Methods Retrospectively, 69 patients with unilateral HNCUP treated in 2 cancer institutes between 2004 and 2014 were included. Diagnosis work-up included for all patients a positron emission tomography-computed tomography. The proportion of p16 positive HNCUP was similar in both centers. All patients were treated with curative intent by initial ipsilateral neck dissection. In one center, all 23 patients underwent UL-RT while in the other center, all 46

after CIR, one patient developed a brain necrosis (grade 2) which was treated with bevacizumab. Conclusion In patients with rare tumor entities of locally advanced, recurrent head-and-neck cancer, CIR is an effective and safe treatment alternative to salvage surgery or palliative systemic therapy in carefully selected patients with good performance status. Further prospective studies are merited to confirm these findings. EP-1156 Radical radio-chemotherapy in head and cancer: retrospective comparison between weekly and 3-weekly CDDP. M. Buglione 1 , M. Gerardi 2 , D. Greco 1 , M. Maddalo 1 , A. Daniela 2 , M. Bonù 1 , M. Augugliaro 3 , A. Alghisi 1 , L. Pegurri 1 , A. Ferrari 2 , D. Tomasini 1 , G. Marvaso 2 , R. Orecchia 4 , B. Jereczek 3 , S.M. Magrini 1 1 University and Spedali Civili - Brescia, Radiation Oncology Unit, Brescia, Italy ; 2 IEO- European Institute of Oncology IRCCS, Division of Radiation Oncology, Milano, Italy ; 3 IEO- European Institute of Oncology IRCCS and University of Milano, Division of Radiation Oncology and Oncology and Hemato-Oncology Department, Milano, Italy ; 4 IEO- European Institute of Oncology IRCCS, Scientific Direction, Milano, Italy Purpose or Objective Even if three weekly (3w) CDDP is considered the standard chemotherapy given concurrently with radiotherapy in the treatment of head and neck cancer, the alternative use of weekly (w) CDDP is widely adopted, because is thought to be less toxic and more manageable. This retrospective analysis aims to compare toxicity and survival of these two schedules. Material and Methods Patients eligible for the analysis had meso/hypo- pharyngeal or laryngeal locally advanced disease and were treated with radical radio-chemotherapy. Patient, disease and treatment characteristics were analysed and related with toxicity and survival, using χ2-test, log-rank test and propensity score (age, T, N, M) analysis (SPSS®). Results Between Jan 2010 and Jan 2017 166 patients were treated in two large reference Italian Centres, 52 pts with 3w (100mg/m 2 ) and 114 pts with w-CDDP (40mg/m 2 ). Patients treated with w-CDDP had a statistically significant older age (p=0.005), worse Karnofsky performance (p=0.000); higher smoking and alcohol consumption (p=0.000). Moreover, in this group there were less meso-pharyngeal (65% vs 90%; p=0.001) and N2- 3 disease (71% vs 84.7% p=0.02) and more T3-4 disease (54% vs 38%; p=0.05). All patients were treated with equivalent RT doses. The CDDP cumulative doses were equivalent in both groups (p=0.10); the rate of RT interruption was higher in the w group. Clinical response was similar in the two groups (p=0.081 and p=0.984 in relation to N and T response, respectively). Local relapse rate is higher in w-group (17.65% vs 11.5%) while metastases occurrence is worse in 3w-group (4.4% vs 19.2%) (p=0.01). Anaemia, leukopenia, renal toxicity, mucositis and dysphagia rates were similar in the two groups. Thrombocytopenia, nausea and vomiting were more frequent in the w-group (p=0.01 and 0,007 respectively). Overall survival was influenced by tumour site (better for meso-pharyngeal disease p=0.04), nodal stage (better for N0-1 p=0.01), and nodal response to treatment (better for CR p=0.004) but not by the CDDP schedule (p=0.433). Relapse free survival was influenced only by the nodal response to treatment (better for CR, p=0.015). All survival data were confirmed after propensity score analysis. Conclusion With the limits of a retrospective analysis the study showed the equivalence of the two CDDP schedules in