ESTRO 36 Abstract Book

S88 ESTRO 36 2017 _______________________________________________________________________________________________

In all treatments constraints to rectum, bladder and urethra were met. Average dose to the treatment volume was D95: 18.9Gy (SD 2.4Gy). On average 9.4 catheters (range 6-13) were used. Treatment volume was on average 7.4cc (SD2.9cc). With a median follow-up of 6 months (range 1-24 months) a biochemical recurrence according to Phoenix criteria (rise of > 2 ng/mL) had occurred in 1 of 17 patients. There was one patient with late grade 3 urinary incontinence toxicity. Conclusion Focal salvage treatment for local recurrence after primary external beam radiotherapy or brachytherapy is an effective treatment modality with regards to acute toxicity. Whether this treatment option might lead to cure or successfully postpone ADT with acceptable long term toxicity needs further investigation. OC-0174 Salvage LDR-brachytherapy for recurrent prostate cancer: results from a single institution S. Magrini 1 , F. Barbera 1 1 Spedali Civili di Brescia, Department of Radiation Oncology "Istituto del Radio", Brescia, Italy Purpose or Objective To evaluate the results of whole gland salvage brachytherapy (SBT) after primary external beam radiotherapy in terms of toxicity/QoL and efficacy. Material and Methods We retrospectively analyzed the clinical data of 19 patients consecutively treated with SBT at our Institution from June 2012 through November 2015. Local recurrences were identified with 11C-Choline PET/CT and MRI after biochemical recurrence according to Phoenix criteria. The prescription dose was 130Gy-LDR-BT to the whole prostate gland. Acute and late toxicities were graded with the CTCAE-4.0 scoring system. Data from IPSS (International Prostatic Symptoms Score) and IIEF (International Index of Erectile Function) questionnaires at baseline and at 6, 12 and 24 months after SBT were also reported (higher IPSS and lower IIEF indicate deterioration). Univariate analysis was done to identify predictors of biochemical control and toxicities. Results Median follow up after SBT was 24 months. Observed severe late toxicities were as follows: 2/19 G3 cystitis (10,2%) and 1/19 G4 proctitis (5,3%). Median IPSS scores pre-SBT and after 6,12,24 months were respectively 4,11,12 and 5. Median IIEF score pre-SBT and after 6,12,24 months were respectively 5,2,4 and 4. At the time of analysis 2/19 patients showed biochemical relapse (3- years-FFBF 85,2%). At univariate analysis only interval to relapse after primary EBRT < 70 months (p=0,05) and PSA reduction between pre-and post SBT level > 80% (p=0,008) were significantly related to further biochemical failure. No statistically significant correlations were found between IPSS and IIEF score before SBRT and post treatment toxicity. Conclusion SBT for recurrent prostate cancer after primary EBRT seems to be a feasible treatment for selected patients. The severity of the observed toxicities shows a peak after 6 months/1 year after local re-treatment and then decreases. Early FFBF rates are good. These preliminary results suggest further accrual of patients and the collection of longer term data. OC-0175 Salvage HDR-BT in prostate local recurrence after radiation therapy: Retrospective analysis C. De la Pinta 1 , T. Muñoz 1 , C. Vallejo 1 , S. Sancho 1 , F. López 1 , M. Martin 1 , A. Hervás 1 1 Hospital Ramon y Cajal, Radiation Oncology, Madrid, Spain

The aim of this study was to evaluate the acute and late toxicities and biochemical disease-free survival and overall survival after high-dose-rate brachytherapy as a salvage modality for locally recurrent prostate Between 2007 and 2014, we retrospectively analyzed 20 consecutively patients. Median age of first treatment was 62 years (range 51-73). The majority of the patients in this study (65%) were low risk. 5p received hormonal blockade. 11p received treatment with low-dose-rate brachytherapy (LDR-BT) and 9p received treatment with external beam radiotherapy with median dose of 75Gy (70- 78Gy). Time to biochemical recurrence was 62 months (range 14-119). Median presalvage PSA was 3.72 (range 1,83-12,29). After biochemical relapse, we confirm local recurrence with biopsy. Patients received high-dose-rate brachytherapy (HDR-BT). The schedule was three implantations, every two weeks, with 10,5Gy per implant. By the time of salvage BT, only 1p received ADT. Acute and late genitourinary and gastrointestinal toxicities were graded using Common Terminology Criteria for Adverse Events (CTCv4.0). Overall survival (OS) and biochemical (bDFS) control were calculated using Kaplan-Meier method. Results After first treatment, acute toxicities consisted of genitourinary toxicities grade 1 (3p) and grade 3 (1p). Not late gastrointestinal toxicities. After HDR-BT, acute toxicities consisted of genitourinary grade 1 (4p), grade 2 (5p) and grade 3 (3p), gastrointestinal toxicities grade 1 (3p) and grade 2 (4p) and impotence in 4p. Not acute toxicities grade 4 were reported. Late toxicities consisted of genitourinary grade 3 were observed in 2p. Not grade 4 complications. With a median follow-up after salvage HDR-BT of 47 months (range 11-112 months), local control was achieved on PSA levels in all patients. Among 20 patients studied, 1 lost follow-up and he was excluded from the survival analysis. Using Kaplan-Meier analysis the 2-year and 5-year OS were 100% and 84,2%, respectively. The 2-year and 5-year biochemical disease-free survival (bDFS) were 85% and 81%, respectively. Conclusion Prostate BT is an effective salvage modality in some selected prostate local recurrence patients after radiation therapy. HDR-BT is a good choice to deliver high-dose radiation in prostate recurrence tumors after external beam radiotherapy or LDR-BT. This treatment offers adequate locoregional control with acceptable range of complications. OC-0176 Identifying Patients Who Benefit the Most from Salvage HDR Brachytherapy G. Valdes 1 , A.J. Chang 1 , O. Kenton 1 , A. Cunha 1 , T.D. Solberg 1 , H. I-Chow 1 1 University of Californ ia UCSF, Radiation Oncology, San Francisco CA, U SA Purpose or Objective To use mac hine learning to better identify patients that could benefit from prostate salvage HDRB (HDR brachytherapy). Material and Methods Data was analyzed for 52 consecutively accrued patients that underwent salvage HDRB between 1998 and 2009 for locally recurrent prostate cancer following previous definitive radiation therapy at the University of California, San Francisco (UCSF). All patients were treated with 36 Gy in 6 fractions after pathologic confirmation of locally recurrent disease without evidence of metastatic disease. Determination of biochemical failure after radiotherapy failure. Material and Methods

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