6th ICHNO Abstract Book

6th ICHNO 6 th ICHNO Conference International Conference on innovative approaches in Head and Neck Oncology 16 – 18 March 2017 Barcelona, Spain __________________________________________________________________________________________ page 15

OC-022 Association of patient derived xenograft formation with oral cavity squamous cell cancer outcomes A. Hope 1 , C. Karamboulas 2 , W. Xu 3 , S. Huang 1 , J. Kim 1 , S. Bratman 1 , J. Cho 1 , J. Ringash 1 , M. Giuliani 1 , A. Bayley 1 , J. Waldron 1 , B. Perez-Ordonez 4 , D. Goldstein 5 , J. De Almeida 5 , D. Brown 5 , J. Irish 5 , P. Gullane 5 , R. Gilbert 5 , B. O'Sullivan 1 , L. Ailles 2 1 Princess Margaret Cancer Center/University of Toronto, Radiation Medicine Program/Radiation Oncology, Toronto, Canada 2 Ontario Cancer Institute, Stem Cell and Developmental Biology, Toronto, Canada 3 Princess Margaret Cancer Center, Biostatistics, Toronto, Canada 4 Toronto General Hospital/University of Toronto, Pathology, Toronto, Canada 5 Princess Margaret Cancer Center/University of Toronto, Otolaryngology - Head/Neck Surgery, Toronto, Canada Purpose or Objective To assess correlation between patient derived xenograft formation (PDXF) and clinical outcomes following curative treatment of oral cavity squamous cell carcinoma (OCSCC). Material and Methods Patients undergoing curative surgery for OCSCC had tumor samples extracted and implanted into NSG (Jackson) mice to assess PDXF. Ten tumor samples per patient were implanted in murine flank and time to PDXF from any of the ten samples was recorded. Clinical outcomes for patients were collected prospectively and charts reviewed to confirm patient factors, pathologic details of surgery, adjuvant therapies, patient survival, and tumor outcomes. Univariable and multivariable analyses were performed to determine correlations between PDXF and cancer outcomes and overall survival. Results Between 2007-2015, 243 OCSCC patients had tumor samples explanted to attempt PDXF. Of these, 161 samples demonstrated PDXF, with a median time to PDXF of 50 days. Patients demonstrating PDXF had a high frequency of advanced nodal stage (p<0.01), close margins (p<0.03), and were more likely to receive adjuvant therapy (p<0.02). PDXF+ patients had significantly reduced 5-year overall survival (OS) (47% vs. 65%), higher rate of distant metastases (DM) (22% vs. 6%), and a trend to lower locoregional control (64% vs. 76%). OS was lower for PDXF+ patients in groups treated with surgery alone (64% vs. 88%) or with surgery and adjuvant radiation or radiochemotherapy (52% vs 72%). Patients who demonstrated PDXF within 8 weeks of surgery had lower survival (60% vs 92%, HR: 3.0, p=0.01) and lower locoregional control (70% vs. 90%, HR: 2.43, p=0.02) (see Figure). DM rates were similar for all PDXF patients regardless of time to PDXF, but was significantly higher than for patients who never demonstrated PDXF. Multivariable models of overall survival showed PDXF and nodal status (N0 vs N+) as independently significant (p<0.01).

Conclusion PDXF in patients with OCSCC correlates with poor oncologic outcomes and lower overall survival. PDXF may provide a rapid (<8 week) biomarker to help select patients for the most appropriate adjuvant therapy following definitive surgery. PDXF in patients with OCSCC should be assessed prospectively to determine if this approach is feasible in a multi-institutional setting.

Symposium: New developments in surgery

SP-023 New developments in sentinel node biopsy of head and neck cancer S. Stoeckli 1 1 Kantonsspital St. Gallen, Other, St Gallen, Switzerland Abstract text Sentinel Node Biopsy (SNB) was introduced in the field of head and neck surgical oncology more than fifteen years ago. Meanwhile, the technique has been adopted for the treatment of early oral squamous cell carcinomas in the NCCN and several national guidelines. The feasibility, safety and efficacy has been proven in many published reports and meta-analyses. Several technological developments have considerably improved the process of lymphatic mapping, which consists of reliable detection and safe excision of the lymph nodes at risk and their thorough histopathologic work-up. The lecture reviews the current available evidence on SNB, reflects the most recent large scale studies, and gives an overview on current challenges and future developments. In particular, the role of new tracers, technological tools for tracer detection and possibilities of intraoperative real- time assessment of the seninel nodes are assessed. SP-024 Integrated 3D virtual visualization of pathology and reconstructive planning in head & neck cancer M. Witjes 1 1 UMCG University Medical Center Groningen, Head and neck, Groningen, The Netherlands Abstract text Introduction: 3D surgical planning software does not allow tumor margin visualization which makes it difficult where to plan the cutting planes for the mandibulectomy or maxillectomy. 3D surgical planning is typically based on CT imaging which does not allow adequate tumor delineation. MRI allows for more precise tumor delineation, but is not easily integrated in 3D surgical planning due to limited bone segmentation options. We therefore studied a new strategy based on fusion of CT and MRI imaging in which MRI is used for tumor delineation and CT for planning of the bone cutting planes. Methods: MRI images were projected onto the CT images for data fusion, which is typically supported by radiotherapeutic planning software (Mirada, Mirada Medical). Delineation of the gross tumour volume (GTV) on MRI was performed using a semi-automated brush tool in the software. The CT dataset, supplemented with the MRI- based tumor delineation data, was exported as a DICOM file and a radiotherapeutic structure set (RTSS) file. Converting this data towards the surgical planning software (Proplan, Materialise) required a conversion. A compatibility algorithm was written using Matlab (Mathworks). In the surgical software the cutting planes were planned, utilizing the 3D visualized tumor. Cutting guides were designed, 3D printed and sterilized for use in the OR. Results: Twenty patients were included after being treated with either maxillectomy or mandibulectomy. On