ESTRO 2020 Abstract book

S497 ESTRO 2020

induction CT of OncologyRadiotherapy Head and Neck (GORTEC) NPC 2006 protocol including docetaxel, cisplatin and 5 fluorouracil followed by concomitant chemoradiotherapy. For each patient, two dosimetric-computed tomographies were made: one before the beginning of neo-adjuvant CT and the second after the completion of the three courses. We delineated the tumor volume (GTV T) and lymph node volume (GTV N) on both CTs.We compared the survival outcomes of good responders (>50%) and bad responders according to the Group The average GTV T volume before CT was 51 cm³ (17.5- 221.5). After CT, there was a decrease in GTV T volume with an average of 39% (5.7%-71.5%). The GTV N volume before CT was 65.5 cm³ on average (4- 250.7). The regression of its volume was of 57.9% on average (5.2%-82.3%). After a mean follow up of 22 months (10-43), we noted 6 metastatic relapses (25%) and three death (12,5%). Overall survival (OS) and metastatic disease-free survival (MDFS) at 2 years were respectively 91.7% and 77.4%. The OS and the MDFS did not correlate with the response to neoadjuvant CT in both GTV T and N. Conclusion Induction chemotherapy allowed the reduction of macroscopic tumor volume and lymph node volume in the treatment of nasopharyngeal carcinomas. This response to chemotherapy could provide better coverage of the target volume with optimal protection of healthy organs. However, this dosimetric benefit could not be translated into survival profit. A longer follow up and more patients were needed to demonstrate the impact CT response on survivals. PO-0838 Comparison Of Patient And Physician Reported Outcome Treated With Concurrent Chemoradiation T. Shahid 1 , J. Bhattacharya 2 , M. Mukherjee 1 , P. Vijyararaghvan 3 , A. De 2 1 Apollo Gleneagles Hospital, Cancer Building- 2nd Floor- Room no 18, Kolkata, India ; 2 Apollo Gleneagles Hospital, Radiotherapy, Kolkata, India ; 3 Apollo Glenagles Hospital, Radiotherapy, Kolkata, India Purpose or Objective Discrepancy of patient reported symptoms and physician reported assessments have been reported and can have significant clinical implication. Goal of these study was to assess the discrepancy of acute toxicities of chemoradiation in locally advanced head and neck carcinomas. Material and Methods 60 patients of locally advanced Squamous Cell carcinomas of Larynx, Oropharynx and Hypopharynx undergoing concurrent chemoradiation were included. Patients below 18 years of age, poor performance status, with history of previous surgery or radiotherapy to neck and neoadjuvant chemotherapy were excluded. All the patients were treated with conventional Radiotherapy fractionation, 66- 70Gy in 30-35Fractions over 6-7 weeks with 3DCRT or IMRT technique and weekly Cisplatin chemotherapy. Acute toxicities were assessed by the physicians using the National Cancer Institute’s Common Terminology Criteria for Adverse Events (CTCAE) for 12 domains at baseline, weekly and at the end of the treatment. Patient reported symptoms for the same domains were recorded using the Patient Reported Outcomes of the CTCAE (PRO-CTCAE) by the patients. Acute Toxicities reported with these two scales were compared and analysed statistically. Results Out of the 60 patients included in the analysis (50 Men, 10 Women, mean [SD] age, 57.4 [8.2] years), 43.3% were Oropharyngeal carcinoma, 11.7% and 80% had T4 and Node positive disease respectively. Comparison of CTCAE and (<50%). Results

PO-0836 Robotic Radiosurgery For Uveal Melanoma: Technique And Results S. CipkinA 1 , M. Mežeckis 1 , V. Buryk 1 1 Sigulda Hospital, Centre of Stereotactic Radiosurgery, Riga, Latvia Purpose or Objective Uveal melanoma (UM) is the most common intraocular malignancy that arises from melanocytes in the iris, ciliary body and most frequently from choroid. Historically, eye enucleation was the only choice for UM treatment. Nowadays, eye preservation can be attempted without impact on overall survival using different forms of focal irradiation (plaque brachytherapy, proton radiotherapy or stereotactic radiosurgery) with low rates of postradiation toxicity. Robotic Stereotactic radiosurgery (RSRS) is the form of precision distant photon irradiation with steep dose gradients that available for the majority of patients with low- and medium sized UM even located in eye eloquent areas (optic disc, iris). The purpose of our study is to show our experience of the Cyberknife M6 radiosurgery in the treatment of patients with uveal melanoma and follow up results. Material and Methods We prospectively followed 10 patients with primary uveal melanoma (UM) who underwent single-fraction robotic radiosurgery with CyberKnife M6 system from June 2016- June 2019. The mean age of the study group at enrollment time was 49.7 [95% confidence interval 39.5-59.9l: Females were 50% [ 46.4-61.6] of all patients. The data of additional research methods confirmed the absence of extrascleral growth and signs of metastasis. All UM located in posterior part of choroid. 3 patients had UM at the level close to optic disk. The median tumor volume before treatment was -1.11cm 3 [ range 0,3-3,71 cm 3 ]. The treatment plan was determined taking into account the size, features of the tumor configuration and the proximity of critical structures. Before treatment, retrobulbar anesthesia was performed. A single dose of 21 Gy (75-80% isodose) was administered. Results Patients with uveal melanoma were followed for a median of 7 months and results were collected. Descriptive and analytical statistics was conducted with SPSS. Comparing results before and after treatment, the volume of tumor decreased median 22.32% (0%-39.50%). No cases of radiation toxicity grade 2-3 was observed, 2 patients had mild conjunctivitis, which was improved after prescribing medications. Vision rates remained stable in all patients after treatment. Conclusion In uveal melanoma patients who had radiosurgery, the study revealed tumor volume reduction after RSRS treatment without or with low rates of postradiation toxicity. The stereotactic radiosurgery is a good alternative to brachytherapy for treating uveal melanoma especial in eloquent eye areas, with protection quality of life and no significant side effects. PO-0837 Does response to induction chemotherapy predicts prognosis for nasopharyngeal carcinoma? M. Wafa 1 , O. Nouri 1 , H. Daoud 1 , F. Najla 1 , S. Tarak 1 , S. Wicem 1 , K. Afef 2 , F. Leila 1 , D. Jamel 1 1 Hbib Bourguiba Hospital, radiotherapy, sfax, Tunisia ; 2 Hbib Bourguiba Hospital, Oncology, sfax, Tunisia Purpose or Objective To evaluate neoadjuvant chemotherapy (CT) response for nasopharyngeal carcinoma (NPC) and its prognostic impact. Material and Methods This is a retrospective study that collected 24 patients with NPC treated with intensity-modulated radiotherapy (IMRT) in our institution between October 2016 and February 2019. All patients received3 courses of