7th ICHNO Abstract book

page 84 7 th ICHNO Conference International Conference on innovative approaches in Head and Neck Oncology 14 – 16 March 2019 Barcelona, Spain __________________________________________________________________________________________ 7th ICHNO

Purpose or Objective Malignant salivary gland tumours (MSGT) are rare with an estimated incidence of 720 cases per year In the UK. There are no published randomised controlled trials looking at the role of post-operative radiotherapy (PORT) in their management. Our objective was to review our local experience regarding the management of MSGT. Material and Methods Patients who underwent surgery for a salivary gland tumour between Jan 2014 and Dec 2017 at our centre were selected (n = 103). Cases were excluded if benign histology, age < 16 or if surgery was the only part of their management conducted at our centre. The final case load was 45 patients. Data was retrospectively collected using electronic records. Results

Conclusion The incidence and prevalence of SCCHN is expected to increase over the next ten years. Population aging, changes in population size, and improvements in survival will drive this increase, despite overall reductions in the age-specific risk of SCCHN across the countries under study. PO-158 Osteoradionecrosis of the mandible after intensity modulated radiation therapy (IMRT) S. Aarup-Kristensen 1 , J. Johansen 2 , C.R. Hansen 2 1 University of Southern Denmark, Oncology, Odense, Denmark; 2 Odense University Hospital, Oncology, Odense, Denmark Purpose or Objective To determine the incidence rate of osteoradionecrosis of the mandible (ORN) in head and neck cancer patients treated with radically intended radiotherapy (RT) and to analyze risk factors in the IMRT era. Material and Methods All patients undergoing radical IMRT for squamous cell carcinoma of the head and neck (SCCHN) in a single oncology center between 2007-2015 where included. A cohort of 1,363 patients was established from the local DAHANCA database, and treatment and demographic data including ORN was extracted. In addition, patient record notes of patients with a visit to the department of Oral and Maxillofacial surgery after IMRT were further investigated to define any additional ORN cases. A nested case-control comparison was performed using controls selected within the same population. Cases and controls were matched 1:2 based on treatment-year and tumor A total of 60 out of 1,363 patients (4,4 %) were recorded with ORN, predominantly in active or former smokers (83 %). Median time to development of ORN was 11 months with the earliest occurrence after only 48 days and the latest 7.5 years after RT. Controls had a median follow-up 34 months after RT. Among cases, 72% had received dental extraction of one or more teeth before IMRT compared with 58% of controls and, equivalently, 48% of cases had undergone surgery prior to IMRT compared with 36% amongst controls. Conclusion ORN is a severe late complication with both early and late onset in head and neck cancer patients treated with RT, however, incidence rates in the IMRT era, as reported here in a large unselected cohort, are modest. Smoking continues to be a significant risk factor, and pre-RT dental extraction as well as surgery was associated with ORN. However, the causality of pre-RT surgery/dental extraction is yet undefined and may be a surrogate for poor dental hygiene. subsite. Results

Figure 1.

At initial biopsy 53% of patients underwent core biopsy rather than FNA. Of those who had FNA as their initial biopsy, 30% subsequently underwent a core biopsy. In 29% of cases the operative histopathology differed from that of the diagnostic biopsy and of those 69% had undergone FNA initially. 62% (n=28) of patients underwent PORT at a dose of 60- 66Gy in 2Gy/ fraction to the high dose area. 89% (n= 25) of those had ipsilateral neck nodal levels irradiated at either high or prophylactic dose. 2 patients had concurrent chemotherapy (cisplatin 35mg/m2 weekly or carboplatin AUC 1.5 weekly). In 43% of cases PORT was indicated on the basis of major criteria and in 32% of cases it was indicated on the basis of 2 or more minor criteria (see fig 1). Patients were followed up for a median of 17 months (range 1 – 47 months). Follow up was shared between Surgical and Oncology teams with baseline imaging post completion of treatment. 93% were still alive at the time

Poster: Salivary gland, skull base, skin and thyroid cancers

PO-159 Retrospective single institution analysis of the management of malignant salivary gland tumours J. Van Griethuysen 1 , A. Khan 1 , A. Thompson 1 1 University College Hospital London UK, Clinical Oncology, London, United Kingdom