Abstract book - ESTRO meets Asia

S99 ESTRO meets Asia 2018

Post EBRT assessment of disease was done by EUA.Following this each patient underwent 2 applications of ICBT with a central tandem and 2 vaginal colpostats. CT simulation was done with a slice thickness of 2.5mm. Bladder and rectal filling protocol was followed for all the patients. Contouring of HRCTV, IRCTV, Organs at risk (OARs) was done as per consensus guidelines for delineation of CTV for CT based brachytherapy in cervical cancer by Akila Viswanathan et al.Dose prescription was 6.5Gy in 4 fractions. Planning was done using point dose optimization on BrachyVisionTM planning system. Reoptimization of plans was done to spare the OARs without compromising on the HRCTV doses. All the patients received treatment on GammamedplusTM remote after loading systems by Varian using an Ir192 source. Results Median age of the cohort was 50 years. Of the 22 patients,11 had stage IIB disease and 11 had stage IIIB disease. The parameters recorded were pre-EBRT disease volume, post-EBRT disease volume, dose to point A, volume of HR-CTV, doses to the bladder and rectum have been recorded. The doses to point A was Right 5.5±0.91, left 5.53±0.86Gy. Volume of HRCTV 49.9±20.36cc,doses to OARs 2cc bladder 5.0±0.87Gy, 2cc rectum 4.35±0.81Gy. Conclusion These results are comparable to studies published with MRI guided ICBT based on GEC-ESTRO guidelines. Hence we would like to conclude that CT guided ICBT is an effective alternative to MRI based brachytherapy technique more so in the third world countries where the incidence of carcinoma cervix is high and two or three MRI guided applications might not be economically feasible. PO-241 Single Institutional Experience of Image guided brachytherapy for Cervical Cancer P. Hirapara 1 , A.K. Patidar 2 , S.D. Bairagya 2 , N. Patel 2 , R. Agarwal 2 , S. Nandeshwar 2 1 HCG Hospital, Radiation Oncology, Bhavnagar, India 2 Shree D B Tejani Lions Cancer Institute, Radiation Oncology, Surat, India Purpose or Objective We report our initial institutional outcome of chemo radiotherapy followed by image guided brachytherapy- IGBT for cervical cancer patients. Material and Methods Biopsy proven cervical cancer patients who were treated from May 2014 to December 2015 with initial External beam radiotherapy (EBRT 50Gy/25 fractions +/- concurrent chemo) followed by computed tomography (CT) guided IGBT. Institutional dose protocol for IGBT was 22.5 Gy/3 Fractions prescribed to point A followed by optimization as required by target coverage and/or dose to organs at risk. Dosimetric parameters & Clinical outcomes [Locoregional Control (LRC), Progression free survival (PFS), Overall survival (OS) & toxicities] were studied to analyse early outcomes. Results Total 123 patients were eligible for analysis after approval from ethics committee. Median age was 52 (30-76year). 68.5% patients were in RTOG performance status 1. 119 (96.7%) patients had squamous cell carcinomas. Fifty-two patients (42.3%) had FIGO stage IIB disease and 50(40.7%) had IIIB disease. Seventy-seven patients (62.6%) had no lymphadenopathy on imaging. Median maximum tumour size was 5 cm and eighty three patients (67.3%) had tumour size ≥4cm. Median EBRT dose was 50Gy(40-60Gy). Parametrical Boost with midline block was used in 13.8% (17/123). Majority patients (91/123) received conventional EBRT (2D-RT) while 26% (32/123) received conformal RT. Only 37.4% (46/123) patients received one to three cycles of neoadjuvant chemotherapy (referral from outside) and 62.6% (77/123) received concurrent

chemotherapy (Inj. Cisplatin 40mg/m 2 weekly). Median duration of gap between EBRT & BT is of 15 days (0-54 days) and median overall treatment duration including CRT & BT is 72 days (44-120 days). Median CT-CTV volume was 70cc (36-144). Median cumulative EQD2 to point A was 82Gy (60-107Gy). Median D90 for the CT-CTV were 82.5Gy (68.9-93.5Gy), and 75.7% patients received more than/equal to prescribed dose (e.g. ≥82.8Gy). Median V100 for CT-CTV was 89.4% (62.7-98.5%). D2cc for the bladder, rectum and sigmoid was 90±5.4Gy, 75±5Gy, 65.7±7Gy respectively. Median value of homogeneity index (HI), TRAK & treated volume is 0.625, 0.5582cGy.m 2 & 96.6cc respectively. Acute grade III skin, gastrointestinal, genitourinary, & haematological toxicities were observed in 10.6%, 33.3%, 1% & 18.7% patients respectively. Response assessment at 3 month post treatment revealed complete response in 58.5% (72/123) patients. At a median follow-up of 30 month (7- 52 months), 3 year LRC, PFS & OS were 77%, 71% & 72% respectively. The overall actuarial risk of grade 3 late skin, rectal morbidity and vaginal fibrosis were 6%, 12% and 13% respectively. We observed grade 3 late bladder toxicity in only 1 patient & sacral fracture in 2 patients on follow up. Conclusion Our initial institutional experience of CCRT resulted in clinical outcomes comparable to standard institutional series. Equal locoregional control was observed even though majority patients presented with bulky tumours. PO-242 Planning risk volume PRV quantification of spinal cord & canal doses in head&neck cancer radiation A. Waheed 1 1 Aga Khan University Hospital, Radiation Oncology, Karachi, Pakistan Purpose or Objective To report the maximum, minimum, mean and 1% of the total dose that is delivered to the spinal cord and spinal canal in definitive treatment of patients of Head and Neck Squamous cell carcinoma. Material and Methods A retrospective study is being conducted on Radiation treatment plans of Head and Neck cancer patients treated between period of 2008 to 2017. A total number of 90 patients plans were reviewed who were treated with radical intent concurrent chemo radiation. As a part of treatment planning OAR (Organs At Risks) like spinal cord and spinal canal are contoured. Total radical doses delivered were in the range of 66-74 Gray. The range of spinal cord and spinal canal doses were analyzed using data extracted from approved plans using Dose Volume Histogram (DVH). Maximum, mean and 1% of total dose delivered to spinal cord and spinal canal during the entire treatment was analyzed. In order to comply with the concepts of PRV (Planning Risk Volume) we have adopted to mark the spinal canal along with spinal cord for planning purposes. As a matter of extra precaution another percentage level was introduced, as 1% dose level, which was also documented and analyzed. Dose Volume Histogram were studied and documented. Results The ranges of maximum, mean and 1% of spinal canal doses were found to be (49.99Gy to 43.08Gy) , (41.66Gy to 13.11Gy) and (39.73Gy to 49.75Gy) respectively. The maximum, mean and 1% doses of all 90 patients was 46.53Gy, 27.38Gy and 44.74Gy. Conclusion A Radical course of RT can be easily delivered in Head and Neck cancer keeping spinal cord doses within acceptable tolerance level.