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Results Growth delay was significantly enhanced by RT in combination with L19-IL2 compared to RT with anti-PD1 for both models (p<0.0001 and p<0.05 for C51 and CT26, respectively). Combination of RT with checkpoint inhibitors resulted in a similar growth delay as RT monotherapy. Upon combining RT+ L19-IL2 with anti- CTLA4, or anti-PDL-1 or anti-PD-1, trimodal treatment was more beneficial than solely RT with L19-IL2 or RT with either immune checkpoint inhibitors (p<0.01), with preference for anti-PD-1 trimodal treatment. Preliminary flow cytometry results indicate a decrease in CD4 populations for all groups and a slight increase in CD8 T cell populations upon L19-IL2 administration. Overall, PD- 1, PDL-1 and CTLA-4 expression on CD8 T cells decreased in the groups where checkpoint inhibitors were given. Conclusion Our results indicate a preference for immunocytokines over immune checkpoint inhibitors when combined with single dose radiotherapy. Interestingly, addition of any checkpoint inhibitor to the combination of RT with the immunocytokine L19-IL2 increased therapeutic efficacy compared with any bimodal treatment. Currently, experiments are ongoing to confirm these results and reveal underlying mechanisms. OC-0056 Evaluation of urinary, sexual and quality of life outcomes after brachytherapy for penile carcinoma D. Gambachidze 1 , C. Lebacle 1 , P. Maroun 1 , A. Escande 1 , A. Bossi 1 , P. Blanchard 1 , E. Deutsch 1,2,3 , C. Haie-Meder 1 , C. Chargari 1,2,3,4,5 1 Institut Gustave Roussy, Radiotherapy Department, Villejuif, France 2 INSERM, U1030, Villejuif, France 3 Université Paris Sud, Université Paris-Saclay, Le Kremlin-Bicêtre, France 4 French Military Health Service Academy, Ecole du Val- de-Grace, Paris, France 5 Institut de Recherche Biomédicale des Armées, D19, Brétigny sur Orge, France Purpose or Objective Brachytherapy is an effective organ preserving treatment for localized penile carcinoma (T1-T2 lesions and < 4cm), providing high local control rates with usually mild to moderate toxicity. However, the long-term functional results of brachytherapy for penile cancer are still insufficiently evaluated. We evaluated urinary function, sexual function and quality of life (QoL) in patients treated with brachytherapy for localized penile cancer. Material and Methods All consecutive patients treated with low-dose rate or pulse-dose rate brachytherapy in our Institute for a localized penile cancer and who were in first complete remission and followed for at least 3 years were included. With the collaboration of two urologic surgeons, a self- reporting questionnaire divided into three parts was sent, in order to assess: 1/ Urinary function, through eight summative questions derived from the International Consultation on Incontinence Questionnaire Male Lower Urinary Tract Symptoms (IQMLUTS) , the Peeling’s voiding picture and research of urethral dilatation or self- catheterization; 2/ Sexual function, through the International Index of Erectile Function (IIEF5) questionnaire; 3/ Cosmetic aspect of the penis, through five questions derived from the Index of Male Genitalia Image questionnaire; 4/ QoL through two questions derived from EuroQol 5 Dimensions questionnaire, one exploring the pain/discomfort dimension and the other using a visual analogue scale. Proffered Papers: CL 1: Genitourinary

Results 39 patients fulfilled inclusion criteria and were sent the questionnaire. Twenty-three patients (59%) answered. Median age was 63.4 years, (Interquartile Range [IR]: 49.7-67.0). Median follow-up was 5.9 years (IR: 5.2-6.7). As regards dosimetric parameters: the median BT dose was 65 Gy (IR: 60-65), the median activation length per needle was 5.0 cm (IR: 3.5-5.5), the median treated volume was 30 cm3 (IR: 12.44-42.52) and the median dose rate was 0.4 Gy/h (IR: 0.4-0.45Gy/h). The different scores showed moderate lower urinary tract symptoms (median IQMLUTS score was 6 (IR: 2-10) and median Pilling score was 2 (IR: 1-3)) . During the follow-up, a urethral dilation or self-catheterization had been necessary in 30% and 13%, respectively. Sixteen (70%) patients continued to maintain a sexual activity and the erectile dysfunction was mild (median IIEF-5 score of 20 (IR: 13-24)). Finally, QoL was good with a median score of 80/100 (IR=65-90) and was only impacted by pain (p=0.02). Overall, 57% and 39% declared having none or moderate pain/discomfort, respectively. Conclusion Although this questionnaire needs to be validated in an independent cohort, our results show the moderate impact of BT on functional outcomes, confirming that it is an adequate first intent organ-sparing strategy in patients with localized penile carcinoma OC-0057 Randomized phase 2 trial of radiation with either gemcitabine or 5FU/cisplatin in bladder cancer W.U. Shipley 1 , P. Zhang 2 , P. Saylor 3 , C. Lee 4 , C.L. Wu 5 , W. Parker 6 , T. Lautenschlaeger 7 , A. Zietman 8 , J. Efstathiou 9 , A. Jani 10 , O. Kucuk 11 , L. Souhami 12 , J. Rodgers 13 , H. Sandler 14 , J. Coen 15 1 Massachusetts Gen. Hosp. RT, Radiation Oncology, Boston MA, USA 2 NRG Oncology, Statistics and Data Management Center- American College of Radiology, Philadelphia, USA 3 Massachusetts General Hospital, Medical Oncology, Boston, USA 4 Ohio State University Comprehensive Cancer Center, Urology, Columbus, USA 5 Massachusetts General Hospital, Pathology, Boston, USA 6 McGill University health Centre, Physics, Montreal, Canada 7 Indiana University, Radiation Oncology, Indianapolis, USA 8 Massachusetts General Hospital, Radiation Oncology, Boston, USA 9 Massachusetts General Hospital, Radiaiton Oncology, Boston, USA 10 Emory University, Radiaiton Oncology, Atlanta, USA 11 Emory University, Medical Oncology, Atlanta, USA 12 McGill University health Centre, Radiation Oncology, Montreal, Canada 13 NRG, Oncology Statistics and Data Management Center, Philadelphia, USA 14 Cedars Sinai Medical Center, Radiation Oncology, Los Angeles, USA 15 21st Century Oncology, Radiation Oncology, Providence, USA Purpose or Objective To assess by a prospective randomized multi-institutional Phase II trial gemcitabine and daily radiation (GD) or 5- FU/cisplatin and twice-daily radiation (FCT) as the chemoradiation (CRT) components of a selective bladder preservation regimen for patients with muscle invasive bladder cancer. Material and Methods Patients with clinical stage T2-4a bladder cancer who were determined to be candidates for a radical cystectomy (RC) if necessary and were randomized to FCT or GD as the CRT component of a selective bladder preservation regimen. Those in the FCT arm received