ESTRO 38 Abstract book

S1180 ESTRO 38

small intestine radio-necrosis. One patient experienced a vaginal necrosis with a bladder fistula, associated with a peritoneal and local tumor progression. In addition vaginal adhesions were reported in 2 and chronic diarrhea in 1 pt. With a 35 months median follow-up (4 – 85 months), 7 patients experienced a local failure (median delay of 22 months after BT, range 11 to 70 months) within the treated volume, isolated in 2 and associated to metastatic progression in 5. Distant metastases alone occurred in 3 pts. Conclusion Interstitial brachytherapy associated with EBRT (+/- concomitant CT) is an effective treatment for locally recurrent gynecological cancers, with favorable clinical outcomes and an acceptable toxicity profile. EP-2134 Developing a IC+IS applicator for treatment of advanced cancer cervix by image based brachytherapy S. Banerjee 1 , V. K 1 , D. Kamaraj 1 , D. Gupta 1 , S. Goyal 1 , S. Bisht 1 , K. Narang 1 , S. Mishra 1 , M. Pinto 2 , P. Manderna 2 , T. Kataria 1 1 Medanta The Medicity, Division of Radiation Oncology, Haryana, India; 2 Medanta The Medicity, Biomedical Engineering, Haryana, India Purpose or Objective The GEC ESTRO initiatives have revolutionized the field of gynecological brachytherapy. Advanced applicators are capable of curative dose even to lateral parametria and allow modulation of dose to the critical organs. The outcomes are visible in terms of local control, and reduced toxicities. However in spite of all the advancements the practice of intracavitary + interstitial (IC+IS) is still restricted to select institutions. Due to limited resource and lack of training in IS techniques advanced applicators are not available where they are most needed. We have developed an IC+IS applicator that is easy to assemble and use. Material and Methods A schematic planning diagram of the applicator was drawn on graphical paper. The size of the applicator, shape, position of the needles in the template (which also serves as fixed ovoid) was determined. First a virtual applicator was constructed in TPS and desired dose distributions were experimented keeping principles of IC + IS brachytherapy planning in mind. The applicator was constructed [Fig 1- End on view of the applicator with central tandem and needles, Fig 2- Lat view applicator with needles]. CT images of the applicator were acquired and the applicator was reconstructed in TPS. We selected 3 cases of interstitial brachytherapy treated in our institute and we contoured exact dimensions of HRCTV on the CT images of the applicator.

cases with a difference of >1.5cm in the S1 measurement and another 2 cases for the pubic bone measurement and in all cases there was no evidence of air gaps and no difference in the soft tissue measured above the cylinder. No correlation was identified between the bladder volume and the angle of the cylinder with any of the measurements or their differences.

Conclusion The use of verification imaging to assess the placement of vaginal cylinders using bony landmarks can provide a rapid confirmation of the correct position. From our cohort there was not much differences in the measurements used between the planning and the verification scans. Soft tissue evaluation showed that within the range of differences in the measurements using bony landmarks the cylinder remained correctly placed; these changes in measurements are likely due to elasticity of the vaginal walls. EP-2133 Interstitial brachytherapy for vaginal recurrence of pelvic gynecological cancers A. Visy 1 , J. Charret 1 , F. Gassa 1 , A. Serre 1 , M. Sandt 1 , F. Lafay 1 , P. Pommier 1 1 Centre Leon Berard, Radiotherapy, Lyon, France Purpose or Objective To date, there are no standard therapy for vaginal recurrences of pelvic gynecological cancers. Local treatment with surgery, External Beam radiotherapy (EBRT) and/or brachytherapy (BT) may be proposed taking into account previous treatments and the extent of the recurrence. Compared to plesioBT, an interstitial implant may permit to deliver a more homogeneous and a higher dose to the tumor. The aim of this study is to evaluate the outcomes of interstitial BT with Iridium192 alone or in addition to surgery, EBRT and/or chemotherapy (CT). Material and Methods From 2011 to 2018, 25 consecutive patients with isolated vaginal recurrences from endometrial (n=15), cervical (n=7), ovarian (n=2) or vaginal cancer (n=1) have been included. The primary treatment included surgery in all but one, EBRT and BT in 1 pt, EBRT in 1pt, and BT in 1 pt. The median time to relapse was 20 months. The site of the recurrence was central (vaginal vault) in 16; lateral in 6, both in 3 pts, with an upper-vaginal “parametrium” extension in 5. A surgery was performed in 6 pts. EBRT (with concomitant CT in 14) was delivered in all patient but one (previously irradiated). Two types of applicators were used according to the site of the recurrence (figure 1 and 2). BT technique was LDR (Iridium wires) in 8 pts treated before 2014 (median dose 19 Gy); PDR in 15 (median dose: 20Gy; 50Gy for exclusive BT) and HDR in 2 pts (12–15Gy in 3 fractions). The cumulative EBRT and BT median dose was: 64 Gy. Results Only 1 grade 2 acute toxicity was observed with BT: a cutaneous abscess on the stitch after BT. Regarding late toxicities, 1 patient required a surgical resection for a