ESTRO 2020 Abstract Book

S639 ESTRO 2020

PO-1214 Stereotactic Body Radiation Therapy in the management of oligometastases from urothelial cancer. C. Franzese 1,2 , G. Francolini 3 , L. Nicosia 4 , F. Alongi 4,5 , L. Livi 3,6 , M. Scorsetti 1,2 1 Humanitas Research Hospital, Radiotherapy and Radiosurgery, Rozzano Milan, Italy ; 2 Humanitas University, Department of Biomedical Sciences, Milan, Italy ; 3 Azienda Ospedaliero-Universitaria Careggi, Radiation Oncology Unit, Firenze, Italy ; 4 IRCCS Sacro Cuore Don Calabria Hospital, Advanced Radiation Oncology Department, Negrar, Italy ; 5 University of Brescia, Radiotherapy unit, Brescia, Italy ; 6 University of Florence, Departments of Biomedical- Experimental- and Clinical Sciences- Radiation Oncology Unit., Firenze, Italy Purpose or Objective Bladder cancer represents the most common type of urothelial carcinoma with poor prognosis in case of metastatic disease. Chemotherapy represent the standard of care for metastatic setting, with a median overall survival (OS) of 12.5 - 15 months. In the present study we aimed to evaluate the role of stereotactic body radiation therapy (SBRT) in the management oligometastatic urothelial cancer. Material and Methods Data were collected from three Institutions to include patients with diagnosis of bladder or other urothelial cancer that developed maximum 5 synchronous or metachronous metastases. Concomitant systemic therapy was allowed. Patients were treated both with Linac or robotic-arm based SBRT. Tumour response was classified according to EORTC-RECIST criteria version 1.16. End points of the present study were the outcome in terms of Local control of treated metastases (LC), out-field progression free survival (dPFS), overall progression free survival (PFS) and OS. Results A total of 82 lesions in 61 patients were treated. Primary tumour was located in bladder in 50 (82%) patients, followed by kidney pelvis (7; 11.5%) and ureter (3; 4.9%). Most common sites of metastatic disease were lung (40.2%) and lymph nodes (35.4%). Twenty-nine patients (47.5%) received 1 to 3 lines of systemic therapy before RT and fourteen (23%) patients had systemic therapy during SBRT. Median BED 10 value was 78.7 Gy (range 37.5 – 151.2). Median follow-up was 17.2 months. Rates of LC at 1 and 2 year were 92% and 88.9%, respectively. Systemic therapy previous to SBRT was predictive of LC (HR 2.62, p = 0.034). Rates of PFS at 1 and 2 year were 47.9% and 38.1%. High number of metastases was negative predictive factor of PFS (HR 2.65, p=0.008). Median OS was 25.6 months. Rates of OS at 1 and 2 year were 78.9% and 50.7%. Total delivered dose (HR 0.93, p= 0.003) and BED 10 (HR 0.97, p=0.006) were correlated with OS. No > grade 2 adverse events were reported in this cohort. Conclusion SBRT represents an effective and safe treatment in the oligometastatic setting from urothelial carcinoma. This local approach is potentially able to delay the onset of new systemic therapies with minimal alteration of patient’s quality of life. PO-1215 Impact of bladder size at radiotherapy planning scan on survival Y.P. Song 1 , A. Choudhury 2 , A. McPartlin 1 , P. Hoskin 2 , A. McWilliam 2 1 The Christie NHS Foundation Trust, Clinical Oncology, Manchester, United Kingdom ; 2 The University of Manchester, Radiotherapy Related Research, Manchester, United Kingdom Purpose or Objective Radiotherapy is the mainstay of curative treatment for bladder cancer patients opting for organ preservation.

observed in 4 irradiated lesions at first year. There was no grade 3 or more acute or late toxicity in the study cohort. Conclusion By providing excellent local control and low toxicity profile, SRT is an effective treatment in oligometastatic RCC patients. The clinical outcomes did not significantly differ for patients who were treated with SRT and received same systemic chemotherapeutic or immunotherapy agent. PO-1213 Pelvic radiotherapy in node positive bladder cancer – outcomes in a selected cohort M. Tjong 1 , I. Lunsky 1 , K. Ajib 2 , S.S. Sridhar 3 , N. Fleshner 2 , A. Zlotta 2 , A. Berlin 1 , G.S. Kulkarni 2 , P. Chung 1 1 Princess Margaret Cancer Centre, Radiation Oncology, Toronto, Canada ; 2 Mount Sinai Hospital, Surgical Oncology, Toronto, Canada ; 3 Princess Margaret Cancer Centre, Medical Oncology, Toronto, Canada Purpose or Objective The presence of clinical nodal metastases in bladder cancer is associated with poor prognosis such that many patients are managed with primary chemotherapy alone without local therapies. Radical cystectomy for local disease control has been reported to be associated with better than expected outcomes especially in those that demonstrate chemo-responsiveness. Radiotherapy (RT)- based treatment in node-negative bladder cancer is gaining wider acceptance for selected patients. However, few data exist using such an approach in patients with nodal metastases (cN+). We examined outcomes in clinically node-positive bladder cancer patients treated with radical radiotherapy. Material and Methods Characteristics, treatment details and outcomes of urothelial bladder patients with cT2-4, cN1-3, cM0 disease treated between January 2003 and April 2017 were retrospectively collected and analyzed. Patients treated with a pelvic dose of less than 50 Gy were excluded. Pelvic locoregional control was defined as absence of pelvic disease, excluding intravesical superficial recurrences. Results A total of 25 patients (6 females) with median age of 67 years (range 51-89) met inclusion criteria. Median ECOG performance status was 1 (range 0-2). Of these 17 were cT2 (9 cN1, 5 cN2, 3 cN3), 3 were cT3 (all cN1), and 5 cT4 (4 cN1, 1 cN2). All patients underwent maximally feasible transurethral resection of bladder tumor (TURBT). Post- TURBT, RT (including bladder boost) was delivered to a median dose of 64 Gy (50-66) in 32 (20-33) fractions. Five were medically unfit for any chemotherapy, 6 had concurrent chemoradiation only, 5 neoadjuvant or consolidation only, and 9 neoadjuvant plus concurrent chemotherapy. Median follow-up was 3.2 years (range 0.2- 9.7), 6 (24%) patients lost to follow-up before 1 year. At three years, overall survival (OS) was 91% (95% Confidence Interval (CI): 69-98%), distant metastasis-free survival (DMFS) was 72% (95% CI: 47-86%), and pelvic locoregional control (PLC) was 84% (95% CI: 57-95%). Of 6 with pelvic failures, 3 had bladder only, 2 had nodal only and one patient had both. Of these, one patient underwent salvage radical cystectomy (RC) post-RT for isolated bladder Overall outcomes were good for this selected cohort of cN+ bladder cancer patients with acceptable pelvic local control rates. With caveat of short follow-up (24% lost to follow-up before 1 year) this suggests that RT-based treatment, similar to surgery may be a reasonable approach for improving pelvic and overall disease control outcomes in selected patients. recurrence. Conclusion