ESTRO 37 Abstract book

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ESTRO 37

analysis of whole-mount sections in 43 patients. Pimonidazole staining was evaluated by an experienced pathologist who determined a hypoxia score (HS Pimo ) for each tumor. An algorithm for pixel-wise integration of fBV and ADC images was developed in a training cohort of 43 patients and validated in an independent cohort of 51 patients. Results A significant positive correlation (R 2 =0.45) was found between fBV and BVD and a negative correlation was found between ADC and CD (R 2 =0.52). The DWI parameters therefore seemed to reflect oxygen supply and consumption, respectively. In addition, negative correlations were found between fBV and HS Pimo and between ADC and HS Pimo , suggesting that both oxygen supply and consumption are determinants of hypoxia in prostate cancer. The image integration algorithm combined ADC and fBV into a hypoxia image that was in good agreement with pimonidazole staining in histological whole-mount sections. Moreover, a strong correlation between HS Pimo and the DWI based hypoxic fraction, HF DWI , was achieved (R 2 =0.70), and this result was confirmed in the validation cohort (R 2 =0.66). Conclusion In conclusion, pixel-wise integration of the DW-MRI parameters ADC and fBV provides a promising method to quantify and visualize tumor hypoxia in prostate cancer patients that may be exploited in hypoxia dose painting. OC-0271 5-Y update of the randomized phase III trial DAHANCA19: Primary (Chemo) RT +/- zalutumumab in HNSCC J.G. Eriksen 1 , C. Maare 2 , J. Johansen 3 , H. Primdahl 4 , J. Evensen 5 , C.A. Kristensen 6 , L.J. Andersen 7 , J. Overgaard 1 1 Aarhus University Hospital, Dept. of Experimental Clinical Oncology, Aarhus, Denmark 2 Herlev Hospital, Dept. of Oncology, Herlev, Denmark 3 Odense University Hospital, Dept. of Oncology, Odense, Denmark 4 Aarhus University Hospital, Dept. of Oncology, Aarhus, Denmark 5 Oslo University Hospital, The Norwegian Radium Hospital, Oslo, Norway 6 Copenhagen University Hospital, Dept. of Oncology, Copenhagen, Denmark 7 Aalborg University Hospital, Dept. of Oncology, Aalborg, Denmark Purpose or Objective Monoclonal antibodies against the Epidermal Growth Factor receptor (EGFR-I) have been reported to increase tumor control and survival of patients with Head and Neck Squamous Cell Carcinomas (HNSCC) when combined with radiotherapy (RT). This study was conducted by the Danish Head and Neck Cancer Group (DAHANCA) and aimed to evaluate if concurrent treatment with the EGFR-I zalutumumab during chemo-RT (C-RT) or RT improved outcome in patients with HNSCC. Material and Methods 619 pts with biopsy-verified HNSCC entered the study from November 2007 to June 2012. The majority of tumors were of oropharyngeal origin (69%) whereas other sites were less represented: oral cavity (4%), hypopharynx (12%) and larynx (14%). Stratification was done by tumor-site, stage (554 (89%) patients were stage III-IV), p16-status (75% of oropharyngeal carcinomas were positive) and use of concomitant cisplatin (71%). Patients were randomized to control-arm or zalutumumab-arm. The control-arm was primary accelerated RT, predominantly 66-68Gy, 2Gy/fx, 6fx/wk and concomitant Proffered Papers: CL 5: Head and neck

daily hypoxic radiosensitisation with nimorazole. Stage III-IV carcinomas received weekly cisplatinum 40 mg/m2 during RT. Elective neck-dissection was not performed. The zalutumumab-arm was identical with the control-arm plus zalutumumab 8 mg/kg. First dose was given the week before start of RT and continued weekly during irradiation. Analyses were performed as intention-to- treat. Primary endpoint was Loco-Regional Control (LRC). Secondary endpoints were Disease Specific Survival (DSS) and Overall Survival (OS). Results Median observation time was 59 months. 608 patients were eligible for analysis. 307 pts were in the control- arm and 301 in the zalutumumab-arm. Patient and tumor parameters were well balanced. The 5-year LRC rate was 70% in the zalutumumab-arm vs. 74% in the control-arm, HR: 1.10 [95% CI: 0.81-1.50]. This outcome was also reflected in DSS: HR 1.12 [0.79-1.60] and in OS: HR 1.17 [0.89-1.52]. There was no benefit of adding zalutumumab to C-RT nor RT alone for any of the endpoints. Treatment was generally well tolerated, but 94% of the pts in the zalutumumab-arm experienced a skin-rash (29% grade 3+4 rash), and pts treated with zalutumumab experienced significantly more frequent confluent mucositis (70% vs. 56%, p=0.001) and grade 3+4 in-field skin reaction (27% vs. 4%, p<0.0001). The 5-year update did not reveal any significant increase in late morbidity between the zalutumumab-arm and control-arm: severe dysphagia (19% vs. 16%), severe dryness of the mouth (20% vs. 18%), severe late oedema (3% vs. 5%), severe atrophia (8% vs. 6%) and severe fibrosis (20% vs. 16%). Conclusion Treatment with zalutumumab was generally well tolerated, but the addition of concomitant zalutumumab to primary C-RT or RT and nimorazole for HNSCC did not increase loco-regional control nor disease specific or overall survival at 5 years. Acute toxicities, but not late morbidity, were increased in the zalutumumab-arm. OC-0272 Twice daily reirradiation with cetuximab vs once daily chemoRT after surgery in head and neck cancer Y. Tao 1 , L. Faivre 2 , A. Laprie 3 , P. Boisselier 4 , C. Ferron 5 , G. Jung 6 , S. Racadot 7 , B. Gery 8 , C. Even 9 , I. Breuskin 9 , J. Bourhis 10 , F. Janot 9 1 Institut Gustave Roussy, radiation oncology, Villejuif, France 2 Institut Gustave Roussy, biostatistics, Villejuif, France 3 Institut Claudius Regaud, radiotherapy, toulouse, France 4 Institut du Cancer Val d’Aurelle, radiotherapy, Montpellier, France 5 Centre Hospitalier Universitaire de Nantes, head and neck surgery, Nantes, Franc 6 Centre Paul Strauss, radiotherapy, Strasbourg, France 7 Centre Léon Berard, radiotherapy, Lyon, France 8 Centre François Baclesse, radiotherapy, Caen, France 9 Institut Gustave Roussy, Head and neck oncology, Villejuif, France 10 CHUV, Radiation oncology, Lausanne, Switzerland Purpose or Objective A previously published randomized trial of patients with recurrent Head and Neck squamous cell carcinoma (HNSCC) has shown that full-dose re-irradiation combined with chemotherapy after salvage surgery significantly improved disease free survival (DFS), but had no significant impact on overall survival. The GETTEC and GORTEC groups performed a randomized phase 2 trial to compare two methods of re-irradiation (once-daily split- course with chemotherapy vs twice-daily with cetuximab) in terms of toxicity and survival. Material and Methods Between June, 2010 and February, 2014, patients were randomly allocated to receive either 60 Gy in split course over 11 weeks combined with concomitant 5FU and