ESTRO 36 Abstract Book

S976 ESTRO 36 2017 _______________________________________________________________________________________________

50 Gy. The dose of brachytherapy was 14 Gy in 2 fractions at intervals of one week, which was applied after 40-50 Gy EBRT Results Reducing dysphagia was observed in 70% of patients in the first group, 54% - in the second group, and 23% - in the third. Two-year overall survival was 36%, 12% and 12% respectively. The median overall survival was 15.7; 9.7 and 6.6 months, respectively. Conclusion Adding intraluminal brachytherapy to EBRT can reduce dysphagia and improve overall survival. EP-1803 Moderate dose-escalation with perioperative HDR brachytherapy in soft tissue sarcomas X. Chen 1 , A. Montero 1 , E. Sanchez 1 , J. De las Heras 2 , O. Hernando 3 , M. Lopez 1 , J. Garcia 4 , J.M. Perez 5 , R. Ciervide 1 , J. Valero 1 , M. Garcia-Aranda 1 , R. Alonso 3 , D. Zucca 4 , M.A. De la Casa 4 , B. Alvarez 1 , J. Marti 4 , L. Alonso 5 , P. Fernandez-Leton 4 , C. Rubio 1 1 Hospital Universitario HM Sanchinarro, Radiation Oncology, Madrid, Spain 2 Hospital Universitario HM Sanchinarro, Orthopaedic Surgery, Madrid, Spain 3 Hospital Universitario HM Puerta del Sur, Radiation Oncology, Madrid, Spain 4 Hospital Universitario HM Sanchinarro, Medical Physics, Madrid, Spain 5 Hospital Universitario HM Puerta del Sur, Medical Physics, Madrid, Spain Purpose or Objective Radiation therapy after conservative surgery improves local control in patients with soft tissue sarcoma. A clear relationship exists between dose and local control. We report our experience about feasibility of perioperative brachytherapy as a moderate dose-escalation approach in the multidisciplinary management of soft tissue sarcoma. Material and Methods From May 2015 to October 2016, 9 patients (p), 5 men and 4 women, with a median age of 63 years (range 7 – 72 years) underwent perioperative brachytherapy (PoBT). Histology: 4 p (44%) liposarcoma, 2 p (22%) desmoid and 1 p (11%) fusocellular sarcoma, 1 p (11%) pleomorphic sarcoma and 1 p (11%) sarcoma NOS. Tumor staging: 4 p T2aN0M0, 5 p T2bN0M0. Tumor location: thigh 5 p (56%), trunk 2 p (22%), arm 1 p (11%), neck 1p (11%). PoBT procedure was performed by using 6F plastic catheters placed on the surgical bed at the time of excision. Eight patients obtained R0 resection and 1 p R1 resection. Catheters were placed perpendicularly to the surgical incision at 1.5- 2 cm intervals to ensure adequate dosimetry. CT simulation with 1.5 mm slice thickness was done in the fourth or fifth day after surgery once the sewer system was retired. A total 16.5 Gy was delivered to the PTV in 3 fractions of 550 cGy separated at least 6 hours. Catheters were retired after the last fraction. Results All p received external beam radiotherapy (EBRT) by using intensity modulated radiotherapy (IMRT) at a dose of 50 Gy in 25 fractions of 2 Gy/day. Five p (56%) underwent pre-operative radiotherapy and 4 p (44%) post-operative radiotherapy. Four patients received chemotherapy before or after radiotherapy. One of the biological characteristics of sarcoma is their relatively low α-β ratio. Assuming the alpha- beta ratio of sarcoma cells as 4 our calculation of tumor BED is as following: (2Gy x 25fx) + (5.5Gy x 3fx) = 114.19Gy which corresponds to an accumulated EQD2Gy for tumor of 76.12Gy. With a median follow-up of 7.8 months (range 3 – 17.6 months), no local failure nor distance progression has been observed. No grade 2 or higher toxicity was observed. Conclusion

Peri-operative brachytherapy is feasible and well tolerated and allows a moderate dose-escalation in patients with soft-tissue sarcomas. EP-1804 Laparoscopic robot-assisted brachytherapy of muscle-invasive bladder cancer: clinical case report F. Mascarenhas 1 , F. Marques 1 , K. Maes 2 , R. Formoso 2 , T. Antunes 1 , S. Germano 1 , S. Faustino 1 1 Hospital da Luz, Radiation Oncology, Lisbon, Portugal 2 Hospital da Luz, Urology, Lisbon, Portugal Purpose or Objective The standard treatment of muscle-invasive of the bladder cancer (MIBC) is radical cystectomy. A significant percentage of this population is elderly, with severe co- morbidities, or without general conditions to radical cystectomy. Integrated brachytherapy in a multimodality conservative approach for bladder preservation is well established and is considered an alternative therapeutic option in selected cases. Material and Methods The authors present a clinical case of an elderly patient with a high grade stage T2aN0M0 bladder muscle-invasive carcinoma submitted to laparoscopic robot-assisted brachytherapy (LRAB) according the Arnhem Radiotherapy Institute, that developed specific catheters for this modality. The selection criteria, the clinical evaluation and all phases of the treatment procedure will be presented. Patient was submitted firstly to three cycles of neoadjuvant chemotherapy with carboplatin and gemcitabine followed by intensity modulated external radiotherapy for the pelvis including bladder and pelvic lymph nodes to a total dose of 40Gy in 20 fractions. After 3 weeks patient was submitted to a partial cystectomy and internal iliac lymph nodes dissection. Three Luneray catethers were inserted over the tumor bed in this surgical procedure and brachytherapy was performed beginning in the same day of surgery and completed in the following three days delivering 25Gy in 10 fractions. Following image represents the bladder implant.

The quality of the implant was evaluated using the homogeneity index (HI) and the overdose index (OI), according to the following formulas: HI= (V 100 -V 150 )/V 100 × 100% OI= V 200 /V 100 × 100% The first pulse of brachytherapy was administered on the same day of the catheters’ implant. After the last pulse, the catheters were removed and then pulled out of the abdomen on the other side. Results For the present case, HI was 62,3% and OI was 19,7%. The excellent tolerance of the treatment and the absence of complications allowed the patient´s hospital discharge the day after the final of brachytherapy. The withdrawal of Foley catheter was performed after 2 weeks. One month after the treatment, the previous symptoms were completely improved and the patient is actually asymptomatic. The short follow-up ensures excellent