Abstract book - ESTRO meets Asia

S54 ESTRO meets Asia 2018

Clinical: head and neck

PO-138 Radiation-induced nasopharyngeal ulcers after IMRT in primary NPC patients: a dose-volume analysis Y. Li 1 , T. Xu 1 , X. Lu 1 , C. Hu 1 1 Fudan University Shanghai Cancer Center, Department of Radiation Oncology, Shanghai, China Purpose or Objective This is a retrospective dose-volume-outcome analysis of radiation-induced nasopharyngeal ulcers (RINU)after intensity modulated radiotherapy in primary nasopharyngeal carcinoma (NPC) patients, with the aim to determine how the radiation doses to nasopharyngeal influence the risk of RINU and prediction of this most serious complication of radiotherapy for NPC. Material and Methods Data from 6023 consecutive and nonselected histologically proven primary NPC patients treated with definite IMRT were collected and 25 patients were diagnosed with nasopharyngeal ulcer and met the diagnosis criteria of RINU. Predictive dosimetric factors were identified by using univariate and multivariate analysis. Results Paired samples t-tests showed all dosimetric factors were significantly correlated with the development of RINU, and these factors were associated closely with each other. (P < 0.001) Multivariate analysis revealed D3cc (dose to 3 ml of the nasopharyngeal) was an independent predictor for RINU (P=0.01); the area under the ROC curve for D3cc was 0.87 (P < 0.001), and the cutoff point 73.67 Gy may be the dose tolerance of the nasopharynx. The primary tumor location, distribution of high dose ‘hot spot’ regions and the location of RINU were consistent.

Conclusion The study indicates that radiation-induced nasopharyngeal ulcers is consist with primary tumor location and ‘hottest spots’ regions and we suggest a D3cc limit of 73.67 Gy for the nasopharyngeal. Physicians should be cautious of such ‘hot spots’ in the nasopharyngeal during IMRT treatment plan optimization, review and approval to avoid this most serious complication of radiotherapy for NPC. PO-139 Compare two Induction Chemotherapys with Concurrent Chemoradiotherapy in Nasopharyngeal Carcinoma. Z. Zeng 1 , L. Liu 1 , R. Yan 1 , L. Tu 1 , Y. Wang 1 , P. Chen 2 1 West China Hospital of Sichuan University, Department of Medical Oncology- Cancer Center and Stat e Key Laboratory of Biotherapy, chengdu, China 2 Sichuan University, Sichuan University West China School of Public Health, Chengdu, China Purpose or Objective Nasopharyngeal carcinoma (NPC) is a particularly prevalent tumour, which is sensitive to radiotherapy (RT) and also effective in chemotherapy. Induction chemotherapy treatment NPC is controversial. The aim of this study was to evaluate the treatment outcomes and toxicities between two induction chemotherapy regimens, with both followed by concurrent chemoradiotherapy. Material and Methods A retrospective study of 113 patients with eligible NPC （ stage III–IV NPC with non-distant metastases ） treated at the West China Hospital Cancer Center between May 2009 and Dec 2014 was conducted. Among them, 58 patients received docetaxel , cisplatin and fluorouracild (TPF), consisting of docetaxel (60 mg/m² IV on day 1) cisplatin (75 mg/m² IV on day 1 or within 3 days), and 5-FU (600 mg/m² IV on days 1 to 5) every 3 weeks, and 55 received gemcitabine and cisplatin (GP: gemcitabine 1000 mg/m² IV on day 1 and day 8, with cisplatin 75 mg/m² IV administered on day 1 or within 3 days) induction chemotherapy. Both groups received CCRT incorporating IMRT and cisplatin-based chemotherapy.