ESTRO 2020 Abstract book

S309 ESTRO 2020

months) based on the score obtained according to the clinical characteristics of the patient (type of cancer, ECOG, age, more of two lines of chemotherapy treatment, previous hospitalizations and the presence of liver metastases). We decided to use the TEACHH model in all hospitalized patients and who present a priori indication of palliative radiotherapy. Results We selected 258 candidate patients for palliative radiotherapy. Radiation therapy was indicated for metastatic bone pain in 38.91% of patients, with haemostatic intention in 10.89%, brain metastases in 22.96%, and finally, for compression of the spinal cord in 17.24% of patients. The remaining 10% were treated for other causes. Of the total patients assessed, 21.77% were in the life expectancy group of 1.7 months; 74.15% in 5 months and 4.08% in 19.9 months. The use of the model allowed us to refuse treatment in 68 (26.46%) patients (30 in the 1.7 month group, 37 in 5 months and 1 in 19.9 months). We planned 31 (12.06%) patients who did not receive death treatment (4 in 1.7 months and 27 in 5 months). Conclusion It is a tool that allows us to administer a palliative treatment or reject it in an adjusted way to each patient taking into account their life expectancy, as well as reducing the rate of untreated planned patients by improving the use of the resources of our service. PH-0525 Radio-immunotherapy versus immunotherapy alone – tolerance and adverse events M. Trommer 1,2,3 , S. Marnitz 1,2,3 , J. Kinsky 1 , A. Adams 4 , M. Hellmich 4 , E. Celik 1 , J.M. Herter 1,3,5 , J. Morgenthaler 1,3 , M. Von Bergwelt-Baildon 2,6 , M. Schlaak 2,7 , S. Theurich 2,6 , C. Baues 1,2,3 1 University Hospital of Cologne, Department of Radiation Oncology, Köln, Germany ; 2 University Hospital of Cologne, Radio Immune-Oncology Consortium RIO, Köln, Germany ; 3 University Hospital of Cologne, Center for Integrated Oncology CIO, Köln, Germany ; 4 University of Cologne- Medical Faculty, Institute of Medical Statistics and Computational Biology, Köln, Germany ; 5 University of Cologne, Center for Molecular Medicine Cologne CMMC, Köln, Germany ; 6 University Hospital- LMU Munich, Department of Medicine III, München, Germany ; 7 University Hospital- LMU Munich, Department of Dermatology and Allergology, München, Germany Purpose or Objective Immune checkpoint inhibition (ICI) has changed oncologic treatment strategies dramatically. Both monotherapy and combination therapies have established themselves not only in the metastatic situation to optimize the effect on the tumor. Radiotherapy (RT) is a highly effective local treatment. Especially local but also systemic adverse events due to RT are well known. The mechanisms by which RT and ICI synergistically modulate the immune response might also affect treatment-related side effects. Severe adverse events due to ICI (CTCAE v.5.0 Grade 3-4) are reported in 17-21% of the patients receiving monotherapy. In this study we retrospectively analyzed patients being treated with PD-1 inhibitors (PD-1i) alone or with additional RT regarding the tolerability of this We screened all patients treated with PD1i at our center between 2013 and 2017 and divided the patients into 2 different treatment groups with (RIT = radio- immunotherapy) or without (IT = immunotherapy alone) combination concept. Material and Methods

additional RT. We collected baseline characteristics, PD1i and RT details, as well as toxicities. Patient characteristics and adverse events were compared by Kruskal-Wallis-test for continuous variables and Pearson's chi-square test for categorical variables. Results 201 patients with different types of malignancies (62.5% malignant melanoma; 18.5% non-small cell lung cancer; 7% renal cell carcinoma; 19% others) could be analyzed. We obtained a median follow up period of 22.3 months until 12/2017. Patients received at least 3 cycles of either pembrolizumab (n=112) or nivolumab (n=89). 153 patients received additional RT. Regarding the incidence of toxicities the most frequent adverse events in the RIT group were fatigue (47.2%) and skin toxicities (45.5%) followed by abdominal (33.3%) and lung (21.8%) problems. In the IT group, most frequent side effects were lung toxicities (19.6%) followed by skin toxicities (18.4%), fatigue (17.6%) and abdominal problems (16.3%). In total, more toxicities were reported when adding RT (8.5% vs 19.4%). The expected IT-related adverse events like lung, thyroid and liver toxicities did not differ statistically significantly in between both treatment groups. At least 1 maximum-grade 3 or 4 adverse event of any cause occurred in 11.5 % of the patients in the IT group and in 6.9 % of those in the RIT group, including 1 grade 4 event (2.1%) in the IT group and 6 grade 4 events (3.9%) in the Patients being treated with radiotherapy and PD-1 inhibitors tend to have more side effects when compared to those receiving PD-1 inhibitors alone. Regarding immunotherapy-related adverse events we observed no statistically significant higher numbers when patients are also treated with RT. The reported higher numbers are most likely due to the side effects of the RT itself. With a rare incidence of grade 3 or 4 toxicities the combination treatment of RIT can be applied safely in clinical routine. PH-0526 Socioeconomic status does not affect survival in patients with brain metastases S. Nagtegaal 1 , A. Claes 1 , S.G. Elias 2 , T.J. Snijders 3 , H.M. Verkooijen 4 , J.J.C. Verhoeff 1 1 umc Utrecht, Radiation Oncology, Utrecht, The Netherlands ; 2 umc Utrecht, Julius Center For Health Sciences And Primary Care, Utrecht, The Netherlands ; 3 umc Utrecht, Neurology, Utrecht, The Netherlands ; 4 umc Utrecht, Imaging Devision, Utrecht, The Netherlands Purpose or Objective In most major cancer sites a low socioeconomic status (SES) is consistently associated with poorer survival. However, the generalizability of these results may be limited due to differences in local healthcare systems. Ideally, a patient’s SES should not affect survival. Therefore, we studied the effect of SES on survival in a cohort of brain metastasis patients. Material and Methods We used a consecutive retrospective cohort of 401 patients treated with stereotactic radiosurgery for brain metastases (BM) in our institute between 2012 and 2017. Patients had one of the five most common primary tumour types: non-small cell lung carcinoma (NSCLC), breast cancer, renal cell carcinoma (RCC), melanoma and gastro- intestinal (GI) tumours. Baseline tumour-specific prognostic factors, taken from the Graded Prognostic Assessment (GPA), were collected. These were age, RIT group . Conclusion