Abstract Book

S890

ESTRO 37

EP-1655 Hypofractionated palliative radiotherapy for bladder cancer P. Vargas Arrabal 1 , I. Tovar 1 , P. Galvan 1 , R. Guerrero 1 , S. Rodriguez 1 , A. Ruiz 1 , R. Ching 1 , R. Del Moral 1 , M. Zurita 1 , J. Exposito 1 , J. Bermejo 1 1 Hospital Universitario Virgen de las Nieves, Radiation Oncology, Granada, Spain Purpose or Objective Bladder cancer is a relatively common tumor. It ranks ninth in terms of the number of cancer diagnoses. However, as in many cases can be cured, it is not among the 10 tumors that cause more deaths. Most of these tumors are poorly advanced when diagnosed and can be cured by removing them with or without a complementary treatment. When the tumor is more advanced, healing can be difficult or impossible and the aim of the treatment is palliative, decreasing or delaying the symptoms. The purpose of our study is to evaluate the role of exclusive palliative radiotherapy in those patients diagnosed with locally advanced bladder cancer who are not candidates for treatment with advanced age chemotherapy or associated comorbidities. To value the role of palliative radiotherapy (RT): identification of optimal candidates, outcome and length of palliation of symptoms and treatment-related toxicity. Material and Methods We retrospectively reviewed 17 patients treated between 2015-2017 with histologically diagnosed locally advanced urothelial carcinoma, not candidates for radical treatment with low perfomance status with advanced locoregional disease, metastatic or recurrent. All patients are treated with three-dimensional (3D) external radiotherapy with the same fractionation scheme: 42.4 Gy in fractionation of 265 cGy / day x 5 days / week. Results With a mean follow-up of 20 months, 100% of patients completed planned course of treatment. The median time to symptom progression is 8 months. The objective tumor response is Complete response: 29.4% (5), Partial / stabilization 70.58% (12). The median time to tumor progression was 8 months. The median overall survival is 10 months. The acute toxicity recorded after RT is genito-urinary G1 47% (8), transient urinary incontinence 35.3% (6), 0% radiation cystitis. Conclusion In patients with advanced urothelial carcinoma and non- subsidiary radical treatment, the exclusive hypo- fractionated palliative RT provides a satisfactory rate of disease control and symptom control with tolerable secondary toxicity. N. Klass 1,2 , I. De Pree 1 , E. Oomen-de Hoop 1 , M. Loi 1 , L. Otto-Vollaard 1 , A. Swaak-Kragten 1 , C. Van Zwienen 1 , J. Nuyttens 1 1 Erasmus MC Cancer Institute, Radiation-Oncology, Rotterdam, The Netherlands 2 University Hospital of Bern- Inselspital- University of Bern, Radiation Oncology, Bern, Switzerland Purpose or Objective Lung cancer is worldwide the most common cause of cancer related death. Most patients with lung cancer are already incurable at diagnosis and their prognosis is very limited. Despite new targeting treatment options, overall EP-1656 Influence factors on limited overall survival in palliative patients with lung cancer

bone only disease correlates with improved PFS only in univariate analysis (p=0.014), but not PTV volume, higher D95, planning objectives nor spinal or non-spinal location, Fig 2. In overall survival analysis by cox- regression, ablative treatment to all lesions is the only significant prognostic factor identified; for systemic disease control, bone only disease correlates with improved outcome whereas there is a trend towards positive outcome for ablative treatment to all lesions, Fig 3. Conclusion The study results showed that promising overall survival can be achieved by SBRT to bony oligometastatic disease, in conjunction with other local ablative treatment. Bone only disease may signify a better overall prognosis. SBRT to bony metastasis resulted in excellent local control along disease course independent of lesion location, PTV volume and D95, though majority of the patients received immediate systemic therapy. EP-1654 Evaluation of tolerability in combined treatment with immune inhibitors and palliative radiotherapy. C. De la Pinta Alonso 1 , E. Fernández-Lizarbe 1 , M. Martín Sánchez 1 , J. Domínguez-Rullán 1 , R. Hernánz De Lucas 1 , C. Vallejo Ocaña 1 , M. Martín Martín 1 , P. Barrionuevo 1 , T. Muñóz Migueláñez 1 , F. López Campos 1 , A. Hervás Morón 1 , S. Sancho García 1 1 Hospital Ramon y Cajal, Radiation Oncology, Madrid, Spain Purpose or Objective Immune checkpoint inhibitors are increasingly used in the treatment of metastatic cancers and associated with immune-related adverse events (ir-AEs) such as endocrine dysfunction or gastrointestinal toxicities. Many patients receiving these agents also receive palliative radiotherapy. We analyzed tolerability of this association treatment in our institution. Material and Methods We analyzed retrospectively 50 patients with metastatic lung cancer (36p), renal cell carcinoma (8p), melanoma (4p), head and neck tumors (1p) and gastrointestinal cancer (1p) who received at least one cycle of CTLA-4, PDL-1 or PD-1 inhibitor and palliative radiation. Ir-AEs, defined using CTCAE v4.0, were tabulated in relation with sequencing, timing and location. Results Median dose of radiotherapy was 26,1Gy (8-30Gy). 19p received radiotherapy in bone lesions and 21p in brain metastases. 4p were treated with anti-CTLA-4 alone, 37p with anti-PD-1 or PDL-1 alone and 9p with both. 28p received concomitant immune checkpoint and palliative radiotherapy. 14/50p patients had ir-AEs. In the concomitant group 6p had mild toxicities and 1p developed severe ir-AEs. There were no associations between the site irradiated and specific ir-AEs. Conclusion Our data suggest the combination of local palliative radiation and CTLA-4 and/or PD1 or PDL1 inhibitors are well tolerated, with manageable ir-AEs that did not appear to be associated with the particular site irradiated. Our conclusions are limited by the heterogeneity of patients and treatments and future confirmatory studies are needed, this information can help guide clinical practice for patients on immune checkpoint therapy who require palliative radiotherapy.