ESTRO 37 Abstract book

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ESTRO 37

Material and Methods PCa patients with limited (<3) nodal recurrence were treated with SBRT, defined as a radiotherapy dose of at least 5 Gy per fraction to a biological effective dose of at least 80 Gy to all metastatic sites. Relapses after SBRT were recorded and compared with the initially treated site. Secondary end points were local control, time to ADT and acute and late toxicity. Results Between November 2014 and June 2017 45 metastases in 29 patients were treated with SBRT. Median age of treated patients was 73.5 years (range 64-88). Regarding the primary treatment of PCa, 22 patients underwent surgery and 7 underwent radical radiotherapy. After surgery, 6 patients underwent adjuvant and 12 salvage radiotherapy. All patients were free from androgen deprivation therapy (ADT) at the time of nodal recurrence detection and all, except one, underwent choline-PET before SBRT. Most patients (67%) received 40 Gy in 5 fractions, while 33% received 45 in 6 fractions. A major biochemical response (≥70% in PSA reduction) was achieved in 16 patients (57%), a partial response (30- 69% in PSA reduction) in 6 patients (19%), a stability in 3 (10%) and a biochemical progression in 4 patients (14%). During follow-up period, with a median of 20.8 months (range 2-48), 12 patients (43%) underwent biochemical progression and 6 patients (24%) underwent imaging- documented progression with bone metastasis. No in-field recurrences were reported. 11 patients (52%) are currently free from progression/recurrence and from any systemic therapy. SBRT was well tolerated: we did not observe any acute or late event. Conclusion Our experience shows that SBRT is a safe, effective and minimally invasive treatment for limited nodal recurrence in oligometastatic prostate cancer. Because of its low toxicity and excellent local control, this treatment represent a feasible option not only to improve the outcome, but also to delay further systemic treatments (and related toxicity) in this subset of patients. EP-1580 Patterns of androgen deprivation therapy use with radiotherapy in post-prostatectomy setting W.L. Ong 1 , F. Foroudi 1 , S. Evans 2 , J. Millar 3 1 Olivia Newton John Cancer and Wellness Centre- Austin Health, Department of Radiation Oncology, Heidelberg, Australia 2 Monash University, Department of Epidemiology and Preventive Medicine, Prahran, Australia 3 Alfred Health, Radiation Oncology Service, Prahran, Australia Purpose or Objective There is increasing evidence that androgen deprivation therapy (ADT) given with radiotherapy (RT) following radical prostatectomy (RP) is associated with overall survival benefits. We aim to evaluate the practice pattern of ADT use in a population-based cohort of Australian men with prostate cancer (CaP) who had RT post-RP. Material and Methods This is a prospective cohort of men with CaP captured in the Prostate Cancer Outcome Registry Victoria (PCOR- Vic), who were treated with RT post-RP, between January 2010 and December 2015. The primary outcome is whether ADT was used with RT. Multivariate logistic regression was used to identify factors influencing the use (or omission) of ADT with RT post-RP.

definitive prostate radiotherapy +/-androgen deprivation therapy (ADT) (N=2). Patients with nodal recurrence confined to the pelvis (up to and including common iliac lymph nodes) were included in this analysis. Treatment consisted of 45-56Gy to the bilateral elective pelvic lymph nodes, with a simultaneous integrated boost of 55-70Gy to the involved node(s), delivered in 25-33 fractions. The prostate bed was treated to 59.4-66Gy in 10 post-prostatectomy patients who had not received prior prostate bed RT. No patients received concurrent ADT during treatment. Acute toxicity was documented electronically, and graded retrospectively in accordance with CTCAE v4.03. Following treatment, patients attended for clinical review and PSA evaluation on a 3-6 monthly basis. Results 34 patients with nodal relapse detected on 68 Ga-PSMA PET underwent SNRT, with a median follow-up of 13.6 months (range 3-17 months). The median PSA prior to treatment was 0.86 (range 0.15-9.2). 91%(31/34) men had a reduction in the PSA post-treatment, with 32%(11/34) achieving a PSA nadir of <=0.1 (post RP) or <2ng/mL (post definitive RT). Grade 1 or 2 toxicity was experienced by 28 and 5 patients respectively, consisting of genitourinary or gastrointestinal side effects, or fatigue. At last follow-up, 38%(13/34) patients have experienced biochemical progression; of these - 6 have been commenced on ADT at a median of 8.7 months (range 3- 15) post-treatment. No patients have had clinical progression or have died. Conclusion Nodal salvage radiotherapy is well tolerated with minimal acute toxicity. Clinically significant biochemical response is observed in the majority of patients without ADT. Longer follow-up is required to assess rates of biochemical and clinical progression and prognostic features to aid in patient selection for SNRT. EP-1579 SBRT for limited lymph node recurrence in patients with prostate cancer I. Renna 1 , E. Lattanzi 1 , M. Galaverni 1 , G. Timon 1 , F. Vigo 1 , M. Galeandro 1 , A. Rosca 1 , D. Ramundo 1 , P. Ciammella 1 , L. Giaccherini 1 , F. Bellafiore 1 , M.P. Ruggieri 1 , R. Sghedoni 2 , A. Botti 2 , M. Orlandi 2 , C. Iotti 1 1 AUSL-IRCCS- Reggio Emilia, Oncology and advanced technologies- U.O.C. Radioterapia Oncologica, Reggio Emilia, Italy 2 AUSL-IRCCS- Reggio Emilia, Oncology and advanced technologies- Servizio di Fisica Medica, Reggio Emilia, Italy Purpose or Objective The optimal management of limited nodal prostate cancer (PCa) recurrences after primary treatment remains largely undefined. These patients are usually treated by androgen deprivation therapy (ADT), with detrimental effect on general health and quality of life. In the recent years there is a growing interest for the locoregional treatment. Stereotactic body radiation therapy (SBRT), that allows the delivery of high tumor ablative doses with low toxicity, can potentially cure or, at least, improve prognosis and prolong tumor control and survival. The aim of this monocentric prospective trial is to explore the role of SBRT in patients affected by PCa with limited nodal relapse in order to assess the overall response rates and the delay of systemic treatments (and related toxicity).