6th ICHNO Abstract Book

page 26 6 th ICHNO Conference International Conference on innovative approaches in Head and Neck Oncology 16 – 18 March 2017 Barcelona, Spain __________________________________________________________________________________________ 6th ICHNO

Human papillomavirus-related (HPV+) oropharyngeal cancer is a rapidly emerging disease in many countries that differs from tobacco-related and alcohol-related (HPV–) oropharyngeal cancer. HPV+ oropharyngeal carcinoma is now established as a distinct biological entity, being prognosis significantly superior than HPV negative tumor. Some studies suggest that Trans Oral Radical Surgery (TORS) achieves excellents outcomes with less toxicity. Published clinical trials and published clinical data comparing TORS and RT will be presented and discussed as well as the most important ongoing trials. PO-050 The interplay between all-trans-retinoic acid and radiotherapy in inducing cancer stem cell arrest L.G. Marcu 1 , D. Marcu 1 1 University of Oradea, Faculty of Science Department of Physics, Oradea, Romania Purpose or Objective Head and neck cancer stem cells (CSC) display a number of properties that lead to treatment failure. Conventional treatment techniques are unsuccessful in long-term tumour control due to radioresistance of CSCs and their ability to regrow the tumour. Therefore, more targeted therapies are needed. A CSC targeting agent is all-trans- retinoic acid (ATRA) that was shown to induce CSC differentiation, cell cycle arrest and apoptosis in head and neck cancer cell lines. However, the limited data available in the literature indicates that the effect of ATRA is cell line dependent, as it can induce cell arrest in either G 1 or G 2 phase. The aim of this work was to investigate the interplay between ATRA and radiotherapy and to assess the phase-specific treatment outcome. Material and Methods A hierarchical in silico head and neck cancer model has been developed using Monte Carlo techniques. The tumour contains cancer stem cells, differentiated cells and quiescent cells with varying radioresistance. The pre- treatment CSC population given by the model is 5.9%, which changes during treatment. The tumour was treated with hyperfractionated radiotherapy (1.2 Gy twice daily, 5 days a week, 7 weeks) given the higher locoregional control obtained as compared to conventional fractionation. Radiotherapy (RT) was simulated using the Linear Quadratic model and the properties of ATRA were implemented based on literature data. Results The model showed that with cell arrest in G 2 , the effect of ATRA combined with radiotherapy leads to a dose reduction of 28% for the same killing effect as radiotherapy as a sole agent. However, with G 1 arrest cellular response is substandard, requiring an increase in dose of 11.7% as compared to radiation treatment. With larger ATRA doses, when the dual effect of cell arrest and apoptosis was simulated, both G 1 and G 2 arrests led to a significant decrease of total dose required to control the CSC population (see table 1). Poster: Multidisciplinary management

Table 1. The cell cycle phase-dependent effect of ATRA + RT on tumour kill

Conclusion CSC-targeting agents play a critical role in the future of head and neck cancer treatment. While ATRA shows promising early results, it needs more investigations in determining the cell cycle phase-specific arrest for each histopathological tumour type, as well as more quantitative studies to establish the threshold values required for its full potential. While both G 1 and G 2 phase arrests can lead to improved results when combined with radiotherapy, the model showed that the overall outcome is phase-dependent. PO-051 A 7-year overview on advanced nasopharynx’s cancer: features influencing survival outcomes A. Nogueira 1 , M. Teixeira 1 , L. Khouri 2 , F. Branquinho 1 , P. Jacinto 1 1 Coimbra's Portuguese Institute of Oncology, Oncology, Coimbra, Portugal 2 Coimbra's Portuguese Institute of Oncology, Radiotherapy, Coimbra, Portugal Purpose or Objective Our aim was to assess population characteristics, treatment safety and efficacy, PFS, OS and prognostic value of population and treatment’s features. Material and Methods Retrospectively, we analyzed patients treated for advanced nasopharynx’s cancer (stage III, IVA and IVB) from January 2009 to December 2015, in one institute. Clinical files enquiry were revised and SPSS analysis (Kaplan Meier’s method) used for survival analysis. Results All 33 patients, 33.3% females and 66.7% males, had a median diagnosis age of 47 years (15-74 years) and a good performance status (ECOG 0 or 1). History of tobacco and alcohol use was present in 51.5% and 36.4%, respectively, and 39.4% had history of occupational exposure. Epstein Barr DNA test was positive in 21% of them. Histological study revealed undifferentiated carcinoma in 81.8% of cases. Tumors were classified as stage III (45.4%), IVA (27.3%) and IVB (27.3%). In this population, 84.8% underwent concomitant chemoradiotherapy with cisplatin 100 mg/m 2 3/3 weeks. Of those, 32.1% received the 3 planed cycles. Radiotherapy dose was 70.2 Gy/33Fractions/6.5 weeks. 69.7% of patients underwent adjuvant chemotherapy with 5-FU and cisplatin with a median of 2 cycles, mostly with dose reduction. Major acute toxicities were grade 3/4 neutropenia (26%), grade 3 mucositis (13%), nausea and vomiting (8.7% and 4.3%, respectively) and anemia (8.7%). There were major infectious complications in 33.3%. We observed a complete response in 48.3% of patients, partial response in 44.8%, stable diseases in 3.4% and progression in 3.4%. 1 year and 5 year PFS was 72.2% and 46.4% respectively. Infectious complications had a negative correlation with PFS (p<0.0001) and adjuvant chemotherapy had a positive correlation (p = 0.019). 1 year and 5 year OS was 84.3% and 42.6% respectively. Infectious complications and weight loss had a negative correlation with OS (p<0.0001 and p=0.004, respectively)