ESTRO 38 Abstract book

S1192 ESTRO 38

cytoreduction is similar to those described previously in the literature. It is also comparable to those who report conversion to suitability using LHRH agonists, albeit with a more favourable side effect profile. EP-2155 Optimising HDR Prostate Implant, Planning and delivery. A new centre experience R. Farrell 1 , S. Jain 1 , P. Shiels 1 , G. Workman 1 , K. Crowther 1 , D. Mitchell 1 1 Belfast Health and Social Care Trust- City Hospita-, Radiotherapy Department, Belfast, United Kingdom Purpose or Objective High dose rate prostate Brachytherapy (HDR) is a well‐ established method of dose escalation in combination with external beam radiotherapy (EBRT) and research in its use as a monotherapy continues. Having optimised our permanent seed prostate brachytherapy pathway over 500 cases, we wished to prospectively review the HDR pathway from its implementation at our centre. The goal was to minimize anaesthetic time, optimise ultrasound‐based planning and improve patient throughput. Material and Methods Following formal training, mentoring and development of all departmental policies, procedures, work instructions and treatment pathways, 19 steps were identified on the pathway from patient admission to theatre to discharge from recovery. A supernumerary therapeutic radiographer prospectively documented the time for each task and following the initial 10 cases a multi‐disciplinary meeting was held to identify potential areas were time could be saved. This process was repeated to the point were procedural times were consistent and no further significant time gains were identified. Results To date 66 patients have been treated with HDR brachytherapy for prostate, 55 combination cases with External beam radiotherapy and 11 salvage or monotherapy treatments. At the Plan, Do, Study, Act, (PDSA) review of the initial 10 cases, several tasks including pre‐implant contouring and planning catheter position were felt to be unnecessary duplication and a standardised ‘template’ coordinate implant was adopted. Subsequent cohorts clarified dose constraint objectives and defined methods of prioritising dose to target volumes. When required, second check verification was moved to be a parallel process at each task rather than serially. By the 30 th case our procedure time had reduced from 280mins to 175mins, reduction in overall treatment time of 37.5%. Adoption of identified changes in initial implant procedure resulted in 52%reduction in time, from the average of 69mins (1 st 10 cases) to 33mins (11 th ‐30 th case), from probe insertion to grid locking and hence commencement of planning. Additional reviews of time for catheter reconstruction (simplified to a maximum of 4 waypoints along catheter length) and reduction in the number of treatment checks by radiographers saw a further improvement in procedure time, a reduction of 29% was gained from these changes in the process between the grid locking and treatment start, average of 129mins in the 1 st cohort compared to This time and motion study has reduced overall anaesthetic exposure and improved theatre capacity for our HDR cases. We continue to see a reduction in overall treatment time and frequent PDSA reviews highlight any further issues thus ensuring we improve the overall patient experience. 92mins 2 nd . Conclusion

Electronic Poster: Brachytherapy: Miscellaneous

EP-2156 Assessment of Role of ILRT as palliative treatment in advanced esophageal cancer V. Pareek 1 , R. Bhalavat 1 , M. Chandra 1 1 Jupiter Hospital, Radiation Oncology, Mumbai, India Purpose or Objective This study aims to assess the improvement in dysphagia, associated complications and overall and disease‐free survival with intraluminal brachytherapy (ILRT) as palliative care in advanced esophageal cancer Material and Methods Thirty‐four patients were treated with high dose rate ILRT with or without external radiation therapy from 2009 to 2017 at our institute. Patients were assessed for various parameters including disease stage, length of lesion, KPS and as per grade of dysphagia at presentation. The patients received median dose of 6Gy at 1 cm off axis for 2 fractions one week apart. Fourteen patients were treated radically and 20 patients post EBRT. Multivariate analysis was used to assess the predictors for dysphagia improvement. Remissions of dysphagia and other clinical and radiological factors were assessed in the first month post‐treatment, and then in the third, sixth, and twelfth months. The survival rate was compared with some chosen clinical factors using a log‐rank test and the Kaplan‐Meier method. Results Patients were followed up as per standard institute protocol. Median dysphagia free survival was 12 months. Stricture was seen in 3 patients and ulceration noted in another 2 patients. However, no tracheoesophageal fistula or procedure related complications were noted. Complications were seen with the post EBRT group. The overall survival in the cohort was 12 months and was better post EBRT as compared to radical ILRT (p <0.001). On multivariate analysis, stage of disease (p=0.02), size of lesion (p=0.018) and grade of dysphagia (p=0.023) were found to be predictors for improved outcomes with use of ILRT in palliation. Conclusion Brachytherapy in the form of ILRT in advanced esophageal cancer provides good palliation with minimal complications and improved survival and quality of life to patients. EP-2157 Needle-based stepping source electronic brachytherapy – a feasibility study A.M. Ruder 1 , L. Inghelram 1 , F. Schneider 1 , Y. Abo‐ Madyan 1 , M. Ehmann 1 , J. Hesser 1 , F. Wenz 1 , F. Giordano 1 1 Universitaetsklinikum Mannheim, Klinik für Radioonkologie und Strahlentherapie, Mannheim, Germany Purpose or Objective Electronic needle‐based kilovolt (kV) brachytherapy (eBT) may resemble an economic alternative to multi‐catheter (HDR) and permanent seed implantation (PSI) brachytherapy. We have evaluated whether tumors treated with seed implants would have been suitable for electronic brachytherapy. Material and Methods N=5 post‐interventional CT studies of patients who had received PSI with 125 I seeds in tumors were used as templates for planning. We then simulated treatment with a needle applicator (length = 94 mm) of a kilovoltage x‐ ray system (INTRABEAM, Carl Zeiss Meditec AG) using a dwell point stepping (DPS) approach. For planning the dwell points, an algorithm for kV‐dose distribution in tissue of various density was used (Radiance®, GMV Innovating Solutions S.L., Madrid). For dose summation, Radiance dosimetry files were transformed and imported