ESTRO 38 Abstract book

S389 ESTRO 38

with subtotally excised or unresectable lesions and for patients with poor clinical status who are not good candidates for surgery, as well as those wishing a minimally invasive approach, radiotherapy (RT) or radiosurgery (SRS) can be an effective alternative. RT and SRS have been associated with good rates of local control in a 60–90% range, especially in patients with VHL. The aim of this study is to evaluate the efficacy and safety of SRS for patients with diagnosis of intracranial and spinal HB in terms of local control and toxicity. Material and Methods We conducted a retrospective analysis of 22 patients with a total of 37 HB: 23 intracranial HB and 14 spinal HB treated at our Institute from January 2012 until February 2017. A regular clinical and radiological follow-up with MR imaging was scheduled at 4–6 month intervals after SRS procedure. The toxicity was recorded based on CTCAE 3.0v. The radiosurgical procedures were performed using a CyberKnife system, characterized by a 6MV linac mounted on a robotic arm for multiple, non-isocentric, non-coplanar beams sets delivery. Statistical analysis was carried out using SPSS 21. Results Twenty-two patients were followed for a median of 42 months (range 3–72 months). Median age at the time of SRS was 44 years (range 19-79), 8 patients were female and 14 male. The diagnosis of HB was based on the histological findings, except in 7 patients without surgical removal. Seven patients had multiple lesions and 30 patients had a single lesion. The median tumour volume pre-SRS was 417 mm 3 (range, 40-15779 mm 3 ). The mean prescription dose was 18 Gy (range, 10-25 Gy) in 1-5 fractions with median isodose line of 81% (range, 73-88%). Two patients (9%) developed a recurrence, 12 patients (55%) showed stable disease and 8 (36%) partial response. There was no significant toxicity after treatments. Conclusion SRS, both in single and multi-fractions settings, is potentially attractive for patients with VHL disease where multiple HB may develop either concurrently or sequentially and may be difficult to treat or retreat with repeated surgery and/or conventional radiation techniques without the risk of toxicity. Our results show that SRS can be considered a safe and effective treatment for intracranial and spinal HB. PO-0758 Whole brain RT plus concomitant Temozolamide in PCNSL after MTX-HD: a prospective phase II study F. Catucci 1 , S. Chiesa 2 , M. Giraffa 2 , E. Maiolo 3 , F. Beghella 2 , T. Zinicola 2 , S. Hohaus 3 , V. Rufini 4 , V. Valentini 2 , M. Balducci 2 1 Istituto di Radiologia- Fondazione Policlinico Universitario A. Gemelli IRCCS, Dipartimento di Scienze Radiologiche- Radioterapiche ed Ematologiche, Roma, Italy ; 2 Istituto di Radiologia- Fondazione Policlinico Universitario A. Gemelli IRCCS- Università Cattolica del Sacro Cuore, Dipartimento di Scienze Radiologiche- Radioterapiche ed Ematologiche, Roma, Italy ; 3 Istituto di Ematologia - Fondazione Policlinico Universitario A. Gemelli IRCCS- Università Cattolica del Sacro Cuore, Dipartimento di Scienze Radiologiche- Radioterapiche ed Ematologiche, Roma, Italy ; 4 Istituto di Medicina Nucleare - Fondazione Policlinico Universitario A. Gemelli IRCCS- Università Cattolica del Sacro Cuore, Dipartimento di Scienze Radiologiche- Radioterapiche ed Ematologiche, Roma, Italy Poster: Clinical track: Haematology

Purpose or Objective To evaluate the overall survival (OS) in patients affected by primary cerebral lymphoma (PCNSL) treated with radiotherapy (RT) plus Temozolomide (TMZ) after treatment with high dose methotrexate (HD-MTX). Material and Methods Patients with an histological diagnosis of PCNSL, previously treated HD-MTX, were enrolled to receive TMZ concomitant to RT. The whole brain up to C2 leptomeninges received 30 Gy (2 Gy/die), while the total dose to initial site of disease or residual mass, if present, was modulated according to the response to HD-MTX (Complete response = 6 Gy, partial response = 10 Gy, progression disease = 16 Gy). According to our previous dose escalation study, concomitant TMZ was administered at a safety dose level of 75 mg/mq. Results From March 2004 to December 2017, 33 patients were enrolled: 18 males and 15 females. The median age was 64.5 yrs (range 50-76). Twenty-two patients received two cycles of HD-MTX, while 9 only one cycle (because of hematological toxicity) and 2 patients did not received any cycle (due to poor performance status). Nine patients were subjected to macroscopic surgical excision while the remaining patients were only subjected to biopsy. Twenty-five patients were treated with RT plus concomitant TMZ. The median follow up was 80 months (range 3-169), currently, 9 out of 33 patients (27%) are alive (7 without disease and 2 with stable disease), 22 patients died because of disease and 2 patients because of other causes. The median OS of the whole group was 23.1 months with at 1 years OS of 64% and at 3 years OS of 43%. The concomitant use of TMZ showed a significant impact on OS (p = 0.004). Conclusion Although with a limited patients selection, this prospective study demonstrated that the use of TMZ at a dose of 75 mg/mq concomitant to radiotherapy shows better results in terms of OS than radiotherapy alone. PO-0759 Radiotherapy After Primary CHEMotherapy (RAPCHEM): protocol adherence in a Dutch registration study L. Boersma 1 , P. Elkhuizen 2 , R. Houben 3 , E. Van Leeuwen 4 , S. Linn 5 , L. De Munck 6 , R. Pijnappel 7 , L. Strobbe 8 , T. Van Dalen 9 , J. Verloop 6 , A. Voogd 10 , J. Wessling 11 , P. Poortmans 12 1 Maastricht University Medical Centre+, Radiation Oncology Maastro- GROW School for Oncology and Developmental Biology-, Maastricht, The Netherlands ; 2 The Netherlands Cancer Institute, Radiotherapy, Amsterdam, The Netherlands ; 3 Maastro Clinic, Radiotherapy, Maastricht, The Netherlands ; 4 BOOG study Center, not applicable, Amsterdam, The Netherlands ; 5 The Netherlands Cancer Institute, Medical oncology, Amsterdam, The Netherlands ; 6 Comprehensive Cancer Centre Netherlands, Breast cancer, Utrecht, The Netherlands ; 7 University Medical Centre Utrecht, Radiology, Utrecht, The Netherlands ; 8 Canisius Wilhelmina Hospital, Surgery, Nijmegen, The Netherlands ; 9 Diakonessen Hospital, Surgery, Utrecht, The Netherlands ; 10 Maastricht University Medical Centre+, GROW School for Oncology and Developmental Biology-, Maastricht, The Netherlands ; 11 The Netherlands Cancer Institute, Pathology, Amsterdam, The Netherlands ; 12 Instittut Curie, Radiotherapy, Paris, France Purpose or Objective The indications for post-operative radiation therapy (PORT) after primary systemic treatment (PST) for stage I- Poster: Clinical track: Breast