ESTRO 2020 Abstract book

S490 ESTRO 2020

curative CRT.

Technology Co.- Ltd., Hangzhou YITU Healthcare Technology Co.- Ltd., Hangzhou, China

PO-0821 Prognostic Nutritional Index: A Predictive tool of treatment tolerance to head and neck radiotherapy A. George 1 1 Ramiah medical college-Bangalore, Radiation oncology, Kottayam, India Purpose or Objective Head and neck cancer constitutes 1/3 rd of all cancers in developing countries like India and majority of them present as locally advanced disease . Poor nutritional status is common in these patients which influences treatment compliance, quality of life, and survival outcomes posing a major treatment challenge for oncologists in our country. Aim of our study was to assess role of pre-treatment biomarkers like Neutrophil lymphocyte ratio(NLR), Platelet lymphocyte ratio(PLR) and Prognostic nutritional index(PNI) in predicting A prospective observational study on 100 patients who received definitive head and neck radiotherapy from Oct 2018 to July 2019 in our institute.Patient, tumour and treatment characteristics were documented in a structured format.All routine blood tests were done prior to start of treatment. NLR, PLR and PNI (10x S.Albumin + 0.005x Lymphocyte count) was calculated. Cut off values for NLR,PLR,PNI derived based on median values were 3, 152 and 48 respectively. Treatment tolerance in terms of not completing planned treatment,need for parenteral nutrition, unplanned hospitalizations was assessed.The association of NLR,PLR,PNI values with various treatment tolerance factors were assessed using spearmans correlation test and p value <0.05 was considered statistically significant.Patients were followed up 2 monthly intervals and any death or recurrence documented Results The median age in our study group was 59 year with Male:female ratio being 2.2:1.The median Hb, TLC ,NLR,PLR,PNI were 12,4943, 3,162,47 Respectively. 50 patients received radical chemoradiation,34 received adjuvant RT alone and 16 received adjuvant chemoradiation.12 patients did not complete planned radiation fractions,20% patients had treatment breaks(mean -4 days gap) and 20% patients required parenteral nutrition during the course of treatment.4 patients had recurrence and 10 patients died during a median follow up of 6 months. Out of 12% who did not complete planned radiotherapy,66% had PLR>152 and 83% had a PNI < 47 ( p value 0.058) .70% of patients requiring parenteral nutrition during course of treatment had a PNI of < 47( p value 0.08) (Fig 1). Among patients who died 100% had a PNI<47 (p value <0.005) and 80% had a PLR>152.All patients who had recurrence had a PNI< 47 and PLR>152 which was statistically significant (p value 0.003 and 0.03 ). Conclusion Low PNI is predictive of poor treatment tolerance in head and neck cancer patients from developing countries. PNI can be considered as a surrogate marker of both nutritional status and systemic inflammation and hence is an easy and cost effective screening tool to select patients in whom early nutritional and treatment interventions can be made. PO-0822 Dosimetric predictors of hypothyroidism in nasopharyngeal carcinoma patients treated with IMRT L. Zhou 1 , J. Chen 2 , W. Shen 2 , M. Chen 1 , Y. Chen 1 1 Zhejiang Cancer Hospital, Department of Radiation Oncology, Hangzhou, China ; 2 Hangzhou YITU Healthcare treatment tolerance. Material and Methods

Purpose or Objective It has been reported that hypothyroidism (HT) is common in nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiotherapy (IMRT). The purpose of this study is to investigate the risk factors of radiation- induced thyroid dysfunction, then combined clinical factors and dosimetric optimum parameters of the thyroid gland to predict the incidence rate of HT and to guide individualized treatment. Material and Methods A total of 206 patients with histologically proven NPC treated in Cancer Hospital of University of Chinese Academy of Sciences between Jan 2015 and Aug 2018 were included. Inclusion criteria including NPC patients whose thyroid function results were normal before radiotherapy. The pituitary and thyroid were re-contoured by a senior doctor. Dose-volume histogram (DVH) data, including mean dose, absolute volume, V 20 , V 25 , V 30 , V 35 , V 40 , V 45 , V 50, V 55 and V 60 were extracted and used as dosimetric parameters. Thyroid function was determined by the level of thyroid stimulating hormone (TSH), free triiodothyronine (FT3) and free thyroxine (FT4) in serum. A logistic regression analysis model was built to identify predictors related to HT occurred within 2 years. ROC curve was used to obtain cut-off of dosimetric parameters. Results Follow-up of the 206 patients ranges from 6 to 48 months with a median of 19 months. 50.49% (104/206) patients developed HT, which is defined as having TSH concentrations above the reference range (0.380-4.340 μIU/mL) and FT4 concentrations within or lower than the normal range (0.81-1.89 ng/dL). The average dose of thyroid and pituitary is 45.88Gy (42.86-47.98Gy) and 51.91Gy (40.70-59.24Gy) respectively. Our results showed that gender, N-stage, volume, average dose, V 20 and V 50 of thyroid had significant differences between patients with and without HT. Logistic regression analysis showed that N-stage, thyroid volume and V 50 are independent predictors for HT. Radiosensitivity of thyroid decreases with the increasing thyroid volume. Patients with N>1 had a significantly higher incidence (37.38%) of HT than patients with N≤1 (13.11%). The incidence of HT is 54.55% in patients with thyroid V 50 ˃ 24%, while 34.15% for patients with thyroid V 50 ≤ 24%. However, there is no significant correlation between pituitary dose and thyroid The incidence of HT in NPC patients after IMRT was significantly associated with N-stage, thyroid volume and V 50 . Our study found that patients who received radiotherapy for cervical lymph nodes were at greater risk of developing HT. More attention should be paid to patients whose thyroid volumes are less than 12.82cm 3 and have advanced N-stage. Additionally, pituitary dosimetric parameter did not show statistically significant correlation with the morbidity of HT. PO-0823 A nomogram to predict locoregional recurrence for primary mucosal melanoma of the head and neck D. Dong 1 , S. Li 1 , D. Zhao 1 , W. Liu 1 , L. Li 1 , Y. Sun 1 , X. Shaowen 1 , B. Zheng 1 , W. Wang 1 1 Key Laboratory of Carcinogenesis and Translational Research Ministry of Education/Beijing- Department of Radiation Oncology- Peking University Cancer Hospital and Institute- Beijing- China, Radiotherapy Department, Beijing, China Purpose or Objective To evaluate postoperative radiotherapy (PORT) on prognosis for patients with mucosal melanoma of the head and neck (MMHN) and create a specific nomogram to dysfunction. Conclusion