ESTRO 2020 Abstract book

S533 ESTRO 2020

72 - 90%, I 2 =74%), FFP-5 rate of 74% (95% CI 65 -82%, I 2 = 74%), and Grade 3 or 4 AE rate of 8% (95% CI 2 -14%, I 2 = 0%). Sub-group analysis showed that studies with prospective design had higher rates of OS-2 and OS-5 compared with studies of retrospective design (OS-2: 97% versus (vs) 81%, interaction P (IP) = 0.009; OS-5: 95% vs 75%, IP = 0.003) and studies which employed peri-stem cell transplant RT had lower rates of OS-5 compared to studies without stem cell transplant (59% vs 73%, IP = 0.02). Conclusion The meta-analysis provides evidence to suggest that salvage radiotherapy results in encouraging disease control and survival rates. The level of evidence was low emphasizing the need for high quality randomized trials to establish the optimal management strategy for r/r DLBCL. PO-0913 Effectiveness of radiotherapy for patients with indolent non-Hodgkin's lymphoma I. Hadi 1 , A. Schummer 1 , C. Eze 1 , M. Dreyling 2 , C. Belka 1 , M. Li 1 1 University Hospital LMU, Department of Radiation Oncology, Munich, Germany ; 2 University Hospital LMU, Department of Oncology, Munich, Germany Purpose or Objective Radiotherapy is a mainstay of lymphoma therapy. We analyzed the results of patients with indolent non- Hodgkin's lymphoma (iNHL), who were treated with radiation in our clinic, retrospectively. Material and Methods Patients with iNHL treated between 1999 and 2016 were included. The primary endpoint of this study was progression-free survival (PFS). Secondary endpoints were local control (LC), toxicity and overall survival (OS). PFS, LC, and OS were analyzed using the Kaplan-Meier method. The log-rank test was used to investigate the differences between subgroups. The Cox proportional hazard model was used for univariate continuous analysis. Results Ninety patients were analyzed retrospectively. The median follow-up was 74 months (2-227 months). Stage I after Ann-Arbor was observed in 66 (73.3%), stage II in 19 (21.1%), stage III in 4 patients (4.4%), and stage IV in 1 patient (1.1%). Patients were treated with a median single dose of 2.0 Gy (range: 1.5-2.0 Gy) and a median total dose of 36.0 Gy (range: 16.0-60.0 Gy). Radiotherapy was performed in 2D (n = 17; 18.9%), 3D (n = 70; 77.8%) and IMRT/VMAT (n = 3; 3.3%) techniques. The estimated Kaplan-Meier PFS for 5 and 10 years were 67.3% and 55.8%, respectively (median 102 months). The 5 and 10 year LC was 95.2% and 93.0%, respectively, the median was not reached. The 5- and 10-year-OS were 84% and 73.7%, with a median OS of 137 months. A univariate analysis of PFS showed that modern radiation techniques with 3D/IMRT/VMAT were associated with significantly better 5-year PFS than 2D (71.7% and 44.4%, p= 0.034). Patients who were treated with definitive radiotherapy had significantly improved PFS compared to patients who received any prior treatments (5-year PFS 75.4% and 54.9%, p= 0.016). Dose-escalation >36.0Gy, gender, histology, and age had no prognostic influence on PFS. The most common acute side effects were: dermatitis CTCAE °I-II (n=8), xerostomy CTC °I (n=10), cataract CTC°I (n=9), and dry eyes CTC °I-II (n=11). No serious adverse event CTC° III was reported.

Conclusion Radiotherapy of iNHL demonstrated high effectiveness with no serious side effects in our cohort. Advances in radiation techniques with more precise irradiation volumes and conformal dose coverage was able to reduce toxicity while maintaining the therapeutic effectiveness PO-0914 Impact of HIV infection on consolidative radiotherapy for non-Hodgkin diffuse large B-cell lymphoma C. Trindade Mello Medici 1 , L. Coelho Casimiro 2 , A. Adolfo Guerra Soares Brandão 3 , G.P. Mauro 4 1 Barretos Cancer Hospital, Radiotherapy, Porto Velho, Brazil ; 2 Instituto do Câncer do Estado de São Paulo ICESP, Radiotherapy, Sao Paulo, Brazil ; 3 Instituto do Câncer do Estado de São Paulo ICESP, Hematology, Sao Paulo, Brazil ; 4 University of Sao Paulo, Radiology and Oncology, Sao Paulo, Brazil Purpose or Objective Even though frequent, it is not known how HIV infection and treatment impact in the consolidation by radiotherapy of non-Hodgkin diffuse B-cell lymphomas (DBCL) Material and Methods A retrospective cohort of DBCL patients treated with chemotherapy and consolidative radiotherapy between 2010 and 2018 was assessed. All patients had biopsy- proven lymphoma and were included if radiation was part of the treatment and had at least 6 months of follow-up or were followed until death. Results Three-hundred fifty-nine (359) patients were selected, with a median age at diagnosis of 57.7 years (13-90 years). Median follow-up was 48.0 months. Female patients were 51.3% and most had a good performance in the ECOG scale (78.8% are ECOG 0-1). Median overall survival was not reached, but mean OS was 50.1 months with 86 deaths. Median progression-free survival was 48.7 months. HIV infection had no impact on OS (p=0.580) or PFS (p=0.347) among patients treated with RT. HIV positive patients were more frequently staged only with CT (p>0.05) with no impact on PFS (p=0.191). No HIV positive patient received rituximab due to local policy restrictions and HIV positive patients were more prone to receive CHOP-like chemotherapy (p<0.05), specially ones with etoposide (CHOEP). CHOP was associated with better survival (p=0.015) in the overall population and in the HIV negative population (p=0.002), but not in the HIV positive