ESTRO 37 Abstract book

S1244

ESTRO 37

Purpose or Objective Episcleral plaque brachytherapy (EPB) has gained wide acceptance for the treatment of uveal melanoma because of its potential to preserve vision, salvage the globe, and provide good local control. Our purpose is to evaluated the feasibility and report the outcomes of patients treated with a second course of EPB for locally recurrent posterior uveal melanomas. Material and Methods From 12/02/2001 to 13/02/2017 a total of 834 patients underwent iodine-125 or ruthenium-106 EPB as primary treatment for posterior uveal melanomas at AC Camargo Cancer Center, Sao Paulo, Brazil. This is a retrospective analysis in terms of survival, local control, visual acuity, and eye retention in patients who presented local recurrence and had a second local salvage treatment with EPB. Results Eleven patients (4 men) with median age 60 (range- 42- 81) years met our inclusion criteria. The median time between the first and second EPB was 22.3 (range-27.5). With a median follow up of 58.9 (3-126) months, the actuarial 5-year overall and progression free survival were 42 and 25 months, respectively. All patients evolved with worsening of the visual acuity and or cataract. Other complications observed were maculopathy (two patients) and glaucoma (one patient). Conclusion Salvage EPB should be considered as an alternative to enucleation in patients with local recurrence of posterior uveal melanomas, but taking in account that despite relative successful local control rates, there is predictable decline in the visual acuity. EP-2251 Balloon catheter insertion to extend distance between hepatic tumor lesion and adjacent OAR. P. Hass 1 , I.G. Steffen 2 , M. Powerski 3 , K. Mohnike 4 , M. Seidensticker 5 , F. Meyer 6 , C. Willich 7 , M. Walke 1 , E. Karagiannis 1 , T. Brunner 1 , J. Ricke 5 1 University Hospital Magdeburg, Radiation Oncology, Magdeburg, Germany 2 University Medical Center Charite, Nuclear Medicine, Berlin, Germany 3 University Hospital Magdeburg, Radiology and Nuclear Medicine, Magdeburg, Germany 4 DTZ am Frankfurter Tor, Center for Radiology, Berlin, Germany 5 Ludwig-Maximilians-University LMU, Clinical Radiology, Munich, Germany 6 University Hospital Magdeburg, General- Abdominal and Vascular Surgery, Magdeburg, Germany 7 University Hospital Jena, Radiation Therapy and Radiooncology, Jena, Germany Purpose or Objective Organs at risk (OAR), which are very close to a clinical target volume (CTV) can prevent an effective irradiation of the tumor without a significant risk of serious side effects. The present study investigated the extent of the dosimetric effect of distancing CTV from adjacent OAR’s by means of interventionally applied balloon catheters. Material and Methods Consecutive patients with peripheral predominantly left lobular hepatic malignancies which revealed the critical proximity of an OAR to the CTV in the assessment by gadoxetic acid-enhanced MRI-scans and the preplanning process, underwent also placement of an interventional balloon catheter during CT-guided application of interstitial brachytherapy catheters inserted into the tissue between hepatic capsule and adjacent OAR. The virtual position of the OAR without balloon catheter was anticipated and contoured in addition to contouring of CTV (which is equal to Planning Target Volume [PTV] in brachytherapy), liver and further relevant OAR. The calculated dose values for CTV as well as 1 mL of the

Conclusion A novel multiple channel rectal applicator for contact radiotherapy that uses 192 Ir HDR sources was designed to produce a dose distribution similar to the one obtained by the P50. The use of multiple channels allows the delivery of an optimized dose distribution for the treatment of tumors with different shapes, which is an advantage comparing to current CXRT techniques, with restricted possibilities to change the beam shape.

Electronic Poster: Brachytherapy: Miscellaneous

EP-2250 Salvage second treatment of posterior uveal melanomas with episcleral plaque brachytherapy A.C.A. Pellizzon 1 , M. Silva 1 , R. Fogaroli 1 , D. Guedes 1 , M. Chojniak 2 , M. CHEN 1 , G. GODIN 1 , H. RAMOS 1 , T. COELHO 1 1 ac Camargo Cancer Center, Radiation Oncology, Sao Paulo, Brazil 2 ac Camargo Cancer Center, Oftalmology, Sao Paulo, Brazil