ESTRO 38 Abstract book

S842 ESTRO 38

Fifty-two patients were enrolled at the time of analysis. Median age was 73 years (55-83), Median follow-up was 33 months (range: 6-55 months). Thirty-four (65.3%) had a low-risk PC and 18 (34.6%) an intermediate-risk PC. Median initial PSA was 5.9 ng/ml (range, 1.8-15.7 ng/ml). Median Gleason score was 6 (6-7). Median IPSS pre-SBRT was 4.5 (range, 0 - 7). All patients completed the treatment as planned. Acute G1-2 toxicity occurred in 18 (34.6%) patients and was distributed as follows: 8 (15.3%) cases of G1 gastrointestinal toxicity, 1 (1.9%) patients had G2 gastrointestinal toxicity, 5 (9.6%) patients reported G2 genitourinary toxicity and 11 (21.1%) G1 genitourinary toxicity. Patients may have experienced more than one toxicity. Late G1 gastrointestinal toxicity occurred in 5 (9.6%) patients. No G3 toxicities occurred. At the last follow-up median IPSS was 3 (1-19) and median PSA was 0.315 ng/ml (range 0.04-7.965 ng/ml). Biochemical control was 98%. Conclusion The results of our study showed that FFF SBRT in 5 fractions for low-to-intermediate PC is feasible and well tolerated. Longer follow-up is necessary to assess late toxicity and long-term effectiveness. EP-1559 SBRT for lymph node metastases from prostate cancer: a multi-institutional retrospective analysis F. Alongi 1 , L. Nicosia 1 , C. Francese 2 , G. D'Agostino 2 , L. Di Brina 2 , V. Figlia 1 , R. Mazzola 1 , S. Tomatis 2 , M. Scorsetti 2 1 Ospedale Sacro Cuore "Don Calabria", Radiation Oncology, Negrar, Italy ; 2 Humanitas Clinical and Research Hospital, Radiotherapy and Radiosurgery Department, Milan, Italy Purpose or Objective Metastases directed treatment is an emerging strategy for oligometastatic/oligorecurrent/oligoprogressive lymph node metastases from prostate adenocarcinoma. Aim of the present study was to evaluate outcome of patients treated with stereotactic body radiation therapy (SBRT) on lymph node metastases. Material and Methods This is a multi-institutional retrospective analysis, including patients affected by lymph node metastases from prostate adenocarcinoma treated with SBRT. Patients with a maximum of 5 lymph node metastases were included. Concomitant treatment with systemic therapy was allowed. End-points of the analysis were local control (LC), out-of-field progression-free survival (OFPFS), overall progression-free survival (PFS) and overall survival (OS). Results 80 patients and 157 lymph node metastases, treated from 2009 to 2018 were evaluated. Median age was 70.2 years and median PSA before SBRT was 1.88 ng/ml. Median diameter of treated lesion was 37 mm (range 7 – 40 mm). Dose delivered ranged from 25 to 48 Gy in 5 to 12 Gy per fractions (median BED 3Gy 116.67, range 66.67-240). Androgen deprivation therapy was administered concomitantly in 72 lesions. With a median follow-up of 16 months, LC rates at 1- and 3-years were 93% and 86%. In- field progression of disease was observed in 11 (7%) lesions. One and 3-years OFPFS were 59% and 29% while PFS were 49 % and 20%. Median values of OFPFS and PFS were 15 and 11 months, respectively. Rates of OS at 1- and 3-years were 100% and 95%. Conclusion SBRT in the management of lymph node metastases from prostate cancer seems to be an effective approach with high rates of in-field control. Prospective trials are necessary to better select patients who can benefit the most from this ablative focal treatment.

EP-1560 Quality of life after focal salvage high-dose- rate brachytherapy for radiorecurrent prostate cancer M. Van Son 1 , E. Monninkhof 2 , M. Peters 1 , J. Van der Voort van Zyp 1 1 UMC Utrecht, Radiotherapy, Utrecht, The Netherlands ; 2 UMC Utrecht, Epidemiology, Utrecht, The Netherlands Purpose or Objective Despite developments in radiotherapy, prostate cancer recurrences are common. Radiorecurrent disease is usually palliatively treated with androgen deprivation therapy (ADT), exposing patients to harmful side-effects and deterioration of quality of life (QoL). Focal ablative therapy is an emerging curative treatment option aiming to reduce toxicity and preserve QoL. Here, we present our longitudinal analysis of prospectively collected QoL data from recurrent prostate cancer patients treated with focal salvage high-dose-rate brachytherapy (HDR-BT). Material and Methods We included the first consecutive 100 patients who were treated with focal salvage HDR-BT at our institution. QoL was measured with the validated questionnaire EORTC QLQ-PR25, covering the domains urinary symptoms, bowel symptoms and sexual functioning (scoring scale from 0 – 100). Questionnaires were completed at baseline and after 1, 3, 6, 9, 12, 18 and 24 months, and yearly thereafter. All patients had completed at least 3 questionnaires at the time of analysis. A linear mixed effects model for repeated measures was used to assess the course of QoL over time. Furthermore, we assessed potential risk factors for QoL deterioration. For every domain, a separate model was built. Results Median follow-up time was 19.5 months (range 6-62). The mean questionnaire response rate was 86% (range 72-100% between follow-up time points). Median baseline QoL scores were 12 (urinary symptoms), 0 (bowel symptoms) and 50 (sexual functioning). Urinary symptoms and sexual functioning demonstrated clinically relevant changes over time with maximum score differences of 13 and 12 points respectively (>10 points generally being considered relevant change). Bowel symptoms showed small changes over time (<5 points). Figure 1 illustrates the modelled QoL trends per domain, without adjustment for covariates. Urinary symptoms increased in the first month, normalised afterwards and temporarily increased again after two years. Sexual functioning deteriorated in the first six months, but seemed to recover afterwards. Assessment of potential risk factors related to QoL deterioration was only performed for urinary symptoms and sexual functioning, since these domains showed relevant change over time. Urinary symptoms were related to the administered dose to the urethra, genitourinary toxicity (as graded by the CTCAE 4.0), baseline QoL score and biochemical failure after treatment. Sexual functioning was associated with age, size of the irradiated tumour volume, T-stage of the tumour, erectile dysfunction (as graded by the CTCAE 4.0), baseline QoL score and previous use of ADT.