ESTRO 36 Abstract Book

S566 ESTRO 36 _______________________________________________________________________________________________

Electronic Poster: Clinical track: Head and Neck

EP-1026 Clinical Outcomes of Taiwan cT4b OSCC: Toward the Identification of the Optimal Initial Treatment T.C. Yen 1 , C.T. Liao 2 , Y.W. Wen 3 , L.Y. Lee 4 , C.Y. Lin 5 , H.M. Wang 6 , C.H. Lin 7 1 Chang Gung Memorial Hospital, Nuclear Medicine, Taoyuan, Taiwan 2 Chang Gung Memorial Hospital, Otorhinolaryngology- Head and Neck Surgery, Taoyuan, Taiwan 3 Chang Gung University, Clinical Informatics and Medical Statistics Research Center, Taoyuan, Taiwan 4 Chang Gung Memorial Hospital, Pathology, Taoyuan, Taiwan 5 Chang Gung Memorial Hospital, Radiation Oncology, Taoyuan, Taiwan 6 Chang Gung Memorial Hospital, Medical Oncology, Taoyuan, Taiwan Purpose or Objective The NCCN guidelines recommend that patients with oral cavity squamous cell carcinoma (OSCC) and cT4b disease should be either included in clinical trials or treated with a non-surgical approach. However, surgery may be feasible in selected patients with adequate safety margins. Using the nationwide Taiwanese Cancer Registry Database, we examined the prognosis of cT4b OSCC patients in relation to their treatment approach. Material and Methods Of the 18,910 patients with previously untreated first primary OSCC identified between 2004 and 2010, 492 (2.6%) had cT4b tumors. Of them, 327 (66%) received initial treatment with surgery, whereas 165 (34%) were initially treated with a non-surgical approach. Of the latter group, 78 patients subsequently underwent surgery. A 5-year disease-specific survival (DSS) ≥45% was considered as a favorable outcome. 7 Chang Gung Memorial Hospital, Plastic and Reconstructive Surgery, Taoyuan, Taiwan

Results Better 5-year DSS and overall survival (OS) rates were observed in cT4b patients initially treated with surgery (versus non-surgery; DSS, 51% versus 38%; OS, 43% versus 27%, respectively, p <0.001). Of the participants initially treated with surgery, patients with cN0-2 disease had better 5-year survival rates (DSS: cN0, 59%; cN1, 53%; cN2, 46%; OS: cN0, 49%; cN1, 50%; cN2, 37%) than those with cN3 disease (DSS: 0%; OS: 0%). Among cT4b patients who initially received a non-surgical treatment, subjects who subsequently underwent surgery showed better outcomes. Conclusion Primary surgery is performed in approximately two-thirds of cT4b OSCC patients, with cN0-2 cases showing a good prognosis. Patients who initially received a non-surgical approach can subsequently be treated with surgery and achieve favorable outcomes. EP-1027 Evaluation of induction chemotherapy followed by radiation therapy in advanced oropharyngeal cancers R.K. Pothamsetty 1 , B.P. THALIATH 1 , R.R. GHOSH 1 1 Kamala Nehru Memorial Hospital, Radiation Oncology, Allahabad, India Purpose or Objective 1. Evaluation of acute and late radiation morbidity using the RTOG criteria in both arms. 2. Evaluation of loco-regional failures, diffuse free survival and overall survival in both arms. Material and Methods The study design was a prospective, comparative, randomized double arm study involving patients of all age groups of both the sexes, Stage III and Stage IVA oropharyngeal cancer who were biopsy proven squamous cell carcinoma reported to Kamala Nehru Memorial Hospital, Allahabad from February 2014- June 2015. They were subjected to induction chemotherapy as scheduled. Complete and partial responders were randomized into 2 arms: Arm A (Conventional external beam radiotherapy) and Arm B (Intensity modulated radiotherapy). Both the groups