7th ICHNO Abstract book

page 46 7 th ICHNO Conference International Conference on innovative approaches in Head and Neck Oncology 14 – 16 March 2019 Barcelona, Spain __________________________________________________________________________________________ 7th ICHNO

Local Control (LC) rates of 98%, 95% and 92%. Progression free survival (PFS) rates after 1, 2 and 3 years were 90%, 85% and 81%. Conclusion DVH analysis of OAR volumes acute toxicity in patients with NPC receiving concurrent IMRT and chemotherapy. Concurrent chemoradiation with adjuvant chemotherapy using IMRT with an integrated boost concept provides good disease control and overall survival in patients suffering from nasopharyngeal cancer. PO-089 Incidence of hypothyroidism following EBRT in Head and Neck malignancies with DVH predictors V. Pareek 1 , R. Bhalavat 2 , M. Chandra 2 , C. Bakshi 3 , S. Dutta 4 1 Jupiter Hospital, Radiation Oncology, Mumbai, India; 2 Jupiter Hospital, Radiation Oncology, Thane, India; 3 Jupiter Hospital, Medical Oncology, Thane, India; 4 Jupiter Hospital, Oncopathology, Thane, India Purpose or Objective Radiation therapy to head and neck malignancies has a significant impact on the dose to thyroid gland and thereby causing dysfunction of the organ and leading to subclinical or clinical hypothyroidism. The objective of this study was to understand better the associated risk factors for development of hypothyroidism, the onset period, association of patient and treatment related parameters and also the dosimetric parameters leading to hypothyroidism in initial euthyroid head and neck malignancies receiving radiation therapy. The role of treatment techniques with Three dimensional conformal radiotherapy (3DRT) and Intensity modulated radiotherapy (IMRT) was also assessed for better clinical outcomes with respect to development of hypothyroidism. Material and Methods In our prospective, non-randomized, observational study, during the period September 2015 to April 2017, a total of 450 patients with histopathologically proven head and neck squamous cell cancer of various sites, were enrolled as subjects for the study. The cohort included 291 males and 159 females with a median age of 51.5 years. Thyroid function was assessed at baseline and thereafter at 6, 12 and 18 months following the completion of radiotherapy. Development of subclinical or clinical hypothyroidism. Assessment of general characters such as gender, age, Karnofsky performance status (KPS), addiction history, medical comorbidities and weight of thyroid gland were assessed. Detailed thyroid dosimetric parameters including maximum, minimum and mean dose and other dose and volume parameters were assessed through the dose volume histograms (DVH). Results After a median follow up of 12 months, the incidence of subclinical hypothyroidism at 6 months of completion of treatment was 3.3% and incidence of clinical hypothyroidism was 1.3%. Subsequently, the incidence at 12 months was 16.7% and 5.3% respectively. The disease was higher in hypopharyngeal and oropharyngeal lesions. Among general parameters, nodal burden (p = 0.003), chemotherapy (p < 0.001) and tobacco addiction (p = 0.013) were found to be significant risk factors in subsequent development of hypothyroidism. On assessment of dosimetric parameters, on univariate analysis, minimum dose was found to be statistically significant along with V25 – V50 and D10, D20 and D50 parameters. On multivariate analysis, V30 (p = 0.002), V40 (p=0.0004) and V50 (p = 0.0002) were the most statistically significant. The dose parameters found in this study were

This study is registered with ClinicalTrials.gov, number NCT03096184. Results Between Dec 23, 2016, and Jul 17, 2018, we screened 105 and enrolled 87 patients. In the interim analysis (data cutoff date: Oct 1, 2017), with 40 patients(Group A) enrolled, the estimated 6-m PFS was 23.2%. (Fig. 1A). However, unexpected grade 3 to 5 bleeding events occurred in twelve patients (30%): four were grade 3, two were grade 4 and six were fatal. Since then, a flexible dose reduction plan and strict exclusion criteria to prevent bleeding event, and we enrolled another 47 patients (Group B). At the data cutoff date: Oct 1, 2018 ， the 6-m PFS for all patients was 41.9%(Group A: 30.0%, Group B: 54.9%, p=0.113).(Fig. 1B) The 6-m OS for all patients was 57.5%(Group A: 52.5%, Group B: 62.7%, p=0.035). (Fig. 1C) Grade 3 to 5 bleeding events decreased to 12.7% (Group A: 30%): two grade 4 and four were fatal. Other grade 3 or 4 adverse events were hypertension (11 [12.6%]), proteinuria (9[10.3%]), and head-foot syndrome (6 [6.9%]). Subgroup analysis showed that patients treated as second line had both better PFS and OS (Fig. 2). Conclusion The combination of apatinib with oral TGO shows promising efficacy in patients with R/M SCCHN. Bleeding events were frequent but some may have been due to natural history of disease and some can be prevented, and further prospective study is warranted. PO-088 Assessment of acute toxicities in nasopharyngeal carcinoma with IMRT - A tale of two contours V. Pareek 1 1 Jupiter Hospital, Radiation Oncology, Mumbai, India Purpose or Objective To determine dosimetric parameters involving normal organs at risk to predict for acute toxicities in patients with nasopharyngeal carcinoma treated with concurrent intensity-modulated radiation therapy (IMRT) and chemotherapy and assessment of clinical outcomes using oral cavity (OCC) and mucosal surface contouring (MSC) methods Material and Methods A standardized method for the various normal organs at risk were developed and prospectively applied to the radiation treatment plans of 25 patients treated with concurrent IMRT and chemotherapy for NPC. Dose–volume histogram (DVH) data were extracted and analyzed against patient toxicity. Receiver operating characteristic analysis and logistic regression were carried out for both contouring methods. The patients were followed up as per protocol and clinical outcomes assessed. Results Grade ≥3 oral mucosa toxicity occurred in 12% of patients in the study. A highly significant dose–volume relationship between oral mucosa irradiation and acute oral mucosa toxicity was supported by using both oral cavity and mucosal surface contouring techniques. In logistic regression, body weight loss was an independent factor related to grade ≥3 toxicity (p= 0.005, respectively), and the independent factor of dosimetric parameters were V30Gy (p=0.003) and V50Gy (p=0.003) for oral mucositis and DARS structures, respectively. In the receiver operating characteristics curve, the areas under V30Gy was 0.771 (p=0.002), and the areas under V50Gy was 0.728 (p=0.001). There was better sparing of the parotid glands and temporomandibular joints. The median follow-up for the entire cohort was 30 months. The 1-, 2-, and 3-year