151751-Najiba-Chargi

200 CHAPTER 11 MATERIAL AND METHODS This study was performed as a secondary analysis of a prior retrospective study. 6 All data were used in an coded fashion. Because of the retrospective nature of this study, formal informed consent or medical ethical approval was waived at the time of the inception of this study. This research was conducted in accordance with the Declaration of Helsinki and all subsequent legislation. PATIENT AND STUDY DESIGN All patients were treated at the Netherlands Cancer Institute in Amsterdam, The Netherlands, with curative intent. Between January 2008 and December 2015, all 279 consecutive patients with histologically proven squamous cell carcinoma of the oropharynx, hypopharynx, or larynx who were eligible for concomitant primary chemoradiotherapy with three three-weekly cours- es of high dose cisplatin courses at 100mg/m 2 BSA were identified. Patients who were not treated with cisplatin for any reason, and patients who received cisplatin in another regimen such as weekly cisplatin or carboplatin were excluded. Patients without recent CT or MRI scans (less than 3 months) of the head and neck area prior to TL were excluded. Patients who had severe dental artifacts at the level of C3 that impeded accurate assessment of SMM were also excluded. Relevant clinical information such as weight, stature, body mass index (BMI), smoking, AJCC stage according to the 7 th AJCC staging manual and outcome data were retrieved frommedical records. The Adult Comorbidity Evaluation index (ACE-27) was used to measure comorbidities. 17 In oropharyngeal cancer, HPV status was assessed by p16 staining, followed by high-risk HPV PCR for confirmation. Survival data were collected until February 2017. Because of a known vastly better prognosis of HPV-related oropharyngeal cancer, those patients were excluded from survival analysis. CHEMOTHERAPY DOSE-LIMITING TOXICITY Chemotherapy dose-limiting toxicity was defined as any toxicity resulting in a cumulative cisplatin dose of less than 200mg/m 2 . This could be because of a chemotherapy dose-reduc - tion of ≥50% (e.g. due to neutropenia or nephrotoxicity) after the first cycle of treatment, a postponement of treatment of ≥4 days (e.g. in the case of bone marrow suppression) result - ing in the termination of a cycle combined with a dose-reduction, or a definite termination of chemotherapy after the first cycle of therapy. The aim was to complete all three cycles, but if treatment tolerance was perceived to be low, two full cycles of high dose cisplatin was accepted as adequate treatment. CT IMAGE ACQUISITION As part of radiotherapy planning, pre-treatment head and neck CT-imaging in radiationmould was performed in all patients. Patients were immobilized in supine treatment position in a custom-made head-and-neck mask. For planning, contrast-enhanced 3-mm slides CT-scan