Abstract Book

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ESTRO 37

Purpose or Objective Secondary central nervous system lymphoma (SCNSL) is a rare complication(<10%) in patients with NHL and is usually fatal. We intended to assess the clinical outcome in patients with SCNSL attending our centre. Material and Methods Data on patients with SCNSL diagnosed from 2006-17 was collected by retrospective chart review. OS and PFS were assessed by Kaplan Meier method. Results We identified 15 patients with SCNSL and could retrieve data of 12 patients. The median age at presentation was 55 years. The male to female sex ratio was 5:1. At presentation, ECOG PS 3/4, B symptoms, extranodal involvement, bulky disease, bone marrow involvement and increased serum LDH were noted in 6,7,10,3,3 and 6 patients respectively. Majority of patients had DLBCL(75%) and stage IV disease(58.3%). CNS involvement was diagnosed at presentation in 5 and at relapse in 7 patients (median time to CNS relapse 8.23 months). The most common initial chemotherapy regimen was RCHOP21 in 41.7% patients and the median number of cycles was 6. Patients with CNS involvement at presentation received additional high dose IV and IT Methotrexate(MTX). Consolidation RT (30-45 Gy in conventional fractionation) to extracranial site was given in 5(41.7%) patients. CNS lesions were parenchymal, meningeal, a combination of both and ocular in 7,3,1 and 1 patient respectively. Brain biopsy in 3 patients revealed high grade NHL. CSF cytology was positive for atypical lymphocytes in 3 patients. In patients with CNS relapse(n=7), salvage chemotherapy -hyper-CVAD, Rituximab-Bendamustine with ITMTX and RDHAP regimens were used in 1 patient each and palliative metronomic chemotherapy with PEP-C regimen (oral Prednisone,Etoposide,Procarbazine,Cyclophosphamide) was used in 3 patients. All except 2 patients had PD on chemotherapy. Ten(83.3%) patients received CNS directed RT(curative in 8 and palliative in 2). The target volume included whole brain(WB) in 9 and the entire craniospinal axis in 1 patient. The most common curative WBRT dose was 45Gy/25 fractions/5 weeks. All patients tolerated RT well. Grade 2 radiation dermatitis was noted in 2. 60% patients had symptomatic benefit . After completion of RT, neuroimaging showed CR in 1, PR in 4 and PD in 1 patient (no imaging in 4 patients). The median FU duration was 24.63 months. At last FU, 3,1,1,7 patients had CR, PR, SD and PD respectively. 4 patients died due to PD. The estimated median OS was 32.9 months from initial diagnosis and the actuarial rates of OS at 2 and 3 years were 73.3% and 48.9% respectively. From the diagnosis of CNS disease, the median PFS was 9.47 months and the actuarial rates of PFS and OS at 1 year were 43.7% and 71.4% respectively. There was no significant difference in OS and PFS between patients with CNS disease at initial diagnosis or at relapse.

the mean dose to the OARs (except the thyroid gland) was higher and translated into more LYLs as compared to patients treated according to an adult protocol. However, statistical significance was not obtained due to small patient numbers and heterogeneity in disease location. EP-1252 Dosimetric and clinical outcomes of radiotherapy for early-stage lymphoma mediastinal involvement. A. Carnevale 1 , S. Silipigni 1 , O. Annibali 2 , E. Ippolito 1 , C. Greco 1 , M. Miele 1 , B. Santo 1 , M. Fiore 1 , L. Trodella 1 , S. Ramella 1 , G. Avvisati 2 1 campus biomedico Rome, Radiotherapy, Roma, Italy 2 campus biomedico Rome, Ematology, Roma, Italy Purpose or Objective To evaluate the dosimetric and clinical outcomes of involved-field radiotherapy (IF-RT) for patients with early-stage lymphoma with mediastinal involvement Material and Methods Patients with early- stage Hodgkin’s lymphoma and non Hodking’s lymphoma involving the mediastinum were reviewed. All patients received polichemotherapy followed by IF-RT. Three-dimensional conformal radiotherapy (3D-CRT) plans were generated. The dose- volume histograms of the target volume, heart and cardiac cavities, left coronary artery and lungs were evaluated. During the follow up patients underwent periodic cardiologic controls, which included echocardiogram. Toxicity was reported using the Common Terminology Criteria for Adverse Events version 4.02. Results Eighteen patients with early-stage disease with mediastinal involvement (14 Hodgkin’s lymphoma and 4 Non Hodgkin’s lymphoma) treated from December 2008 to October 2016 were retrospectively reviewed. The median age was 27 years (range 16-79). 14 patients had Stage IIA disease and 4 patients had Stage IIB. One patient had a bulky mediastinum at presentation and 12 patients had involvement of both the mediastinum and either cervical or axillary nodes. The median dose to the planning target volume (PTV) was 30.6 Gy (range 19.8-46.8). The mean V20 to the lungs was 12% (range 1-36). The mean V25 to the whole heart and mean dose were 8.5% (range 0-29) and 6,2 Gy (range 0- 16), respectively. The mean V25 to the left atrium was 16.2%(range 0-55). The mean V30 to the left and right ventricle were 0.27% (0-4,8) and 1.95%(0-25), respectively. The mean maximum dose to the left coronary artery was 19.3 Gy (range 1,2-31). At the median follow up of 50 months (range 5-103), we found 2 recurrences and 1 patient dead for disease. At the time of this analysis 16 patients are alive without disease. One patient developed an acute G1 esophagitis (CTCAE 4.2) and 1 patient experienced a reduction of ejection heart fraction. No other late toxicities were reported. Conclusion IF-RT ensures a good outcome, with mild toxicity in patients with early-stage mediastinal lymphoma. Longer follow-up will be needed to accurately determine late effects. EP-1253 Secondary central nervous system lymphoma- clinical experience from a regional cancer centre in India A. Biswas 1 , L. Kashyap 1 , N. Adhikari 1 , A. Gogia 2 , R. Sahoo 2 , A. Sharma 2 , B. Mohanti 1 1 All India Institute of Medical Sciences, Radiotherapy & Oncology, New Delhi, India 2 All India Institute of Medical Sciences, Medical Oncology, New Delhi, India

Conclusion Despite a very high burden of adverse prognostic factors, patients with SCNSL in our study fared better than historical control perhaps due to more liberal yet appropriate use of CNS directed radiotherapy. EP-1254 Role of implantable venous devices in dose distribution: dosimetric and clinical considerations M. Laurans 1 , E. Costa 1 , K. Kirov 1 , D. Lefeuvre 1 , A. Fourquet 1 , Y.M. Kirova 1