ESTRO 37 Abstract book

Conclusion Quality management tools can help for implementation of HFSRT. Analyses of our prospective database will confirm that the procedure is secure without jeopardize clinical outcome. EP-2404 The anastomotic leakage in rectum cancer patients after preoperative radiotherapy K. Osowiecka 1 , A. Sugajska 2 , M. Rucinska 2 1 University of Warmia and Mazury in Olsztyn, Department of Public Health, Olsztyn, Poland 2 University of Warmia and Mazury in Olsztyn, Department of Oncology, Olsztyn, Poland Purpose or Objective Colorectal cancer is one of the leading causes of cancer deaths. Even one third of colorectal cancers affects lower part of intestine – rectum. Locally advanced rectal cancer requires a multidisciplinary approach. Standard treatment includes neoadjuvant radiotherapy or chemoradiotherapy followed by surgery. One of the postoperative complications of this approach is the anastomotic leakage. The aim of this retrospective study was to investigate the frequency of anastomotic leakage followed by the need for reoperation. Material and Methods 110 consecutive patients (71 males and 39 females, age: 42-89 years, median 65 years) with locally advanced rectal adenocarcinoma treated with preoperative short radiotherapy (25Gy in 5 fractions; 75% of patients) or chemoradiotherapy (54Gy in 28 fractions; 25% of patients) and anterior resection in Department of Surgical Oncology in Hospital of the Ministry of Internal Affairs with Warmia and Mazury Oncology Center in Olsztyn between January 2014 and December 2016 were analyzed. Chi-square test was used to compare proportions of reoperation in relation to the treatment-, patient- and disease-related factors. Then the variables were included in the multivariate analysis using logistic regression model. A p value ≤0.05 was considered as statistically significant. Results Reoperation was done in 19 patients (17%). The time interval between primer surgery and reoperation ranged from 2 to 31 days (median 8 days). Reoperation was more frequent in males, older patients, with tumor localized ≥6cm from anus and pathologically positive lymph nodes. In multivariate analysis reoperation rates tended to be higher in age >65 years, OR: 4.34 (95% CI: 1.13-16.66), p=0.03 and in case of upper located tumor, OR: 3.97 (95%CI: 1.13-13.99), p=0.03. Conclusion Almost one fifth of rectum cancer patients after preoperative radio- or chemoradiotherapy in this series needed reoperation because anastomotic leakage. Previously study have shown no association between preoperative radiotherapy and anastomotic leakage. In our study older age and high location of tumor turned out to be related with anastomotic leakage and need for reoperation.

group in medical radiation protection published 'Recommendations for implementation of new techniques and practice”. We followed this report and performed a predictive risk analysis and a retrospective risk analysis. Results Novalis truebeam STX was installed in 2014 in our department, allowing VMAT treatments. This LINAC was also gained to implement stereotactic treatments. First step was to form a stereotactic radiation referent team, including radiation oncologists, medical physicists, medical dosimetrist and radiation therapists. As our hospital can’t provide any neurosurgeon, we decided to implement HFSRT and not SRS. The multidisciplinary team followed specific trainings including: Brainlab academy for IPlan use, IGRT (ExacTrac and CBCT) institutional mentoring, use of frameless stereotactic device from Brainlab, QA program for SRS TPS… We adapted the existing quality process and workflow of the radiation department (Fig1), whichxis separated in 3 phases, divided in several steps: pre-treatment (PT1-9), treatment delivery (TD1-7), billing and follow up (BF1-2). PTS steps are focused on protocols based on scientific literature and a specific organization to secure HFSRT progress (ie 24 hours hospitalization in oncology depart- ment for medical observation after the first fraction).

TDS steps are characterized by attendance of the HFSRT referent team. On BFS steps, we insist on filling out the prospective clinical and dosimetrical stereotactic database created and approved by medical board. First patient was treated in November 2015. We planned a yearly or a biennal reviewing of HFSRT procedure. Our monthly Experience Feedback Committee helped to stop useless and time consuming procedures, which were made to reassure HFSRT referent team. The attendance of HFSRT referent team is now only required during the operational test of a new patient, and not anymore on each fraction of each patient. We stopped to report each intra and inter fraction shifts given by ExacTrac, as we feel now secure with our stereotactic accessories. In January 2017 we validated our HFSRT technique as implemented with Brainlab Novalis circle award. We are enlarging RTT and radiation oncologist allowed to perform HFSRT. We proceed continuing medical education in stereotactic field in order to implement SBRT. On the Deming wheel (Fig2) we try to summarize all means set up to achieve safe stereotactic radiation.