ESTRO 37 Abstract book

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ESTRO 37

elderly patients received RT alone. The lack of use of concurrent or sequential chemotherapy in the elderly with stage III NSCLC suggests that the optimal treatment approach for this vulnerable population remains undefined. PV-0041 Hand grip strength: independent prognostic selection test for OS in stage I NSCLC treated with SBRT S. Peeters 1 , B. Chris 2 , B. Jacques 1 , S. Martijn 3 , D.R. Dirk 4 1 MAASTRO Clinic, Radiation Oncology, Maastricht, The Netherlands 2 Hasselt University, Faculty of Medicine and Life Sciences, Hasselt, Belgium 3 University Maastricht, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht, The Netherlands 4 Maastricht University Medical Center, Radiation Oncology, Maastricht, The Netherlands This abstract is part of the media programme and will be relased on the day of its presentation PV-0042 SBRT for peripheral lung tumors >5 cm: first results of the multicenter phase I/II VOLUMES trial H. Peulen 1,2 , J.J. Sonke 2 , E. Van Werkhoven 3 , M. Werner- Wasik 4 , I. Grills 5 , M. Giuliani 6 , A. Hope 6 , F. Mantel 7 , M. Guckenberger 7,8 , J. Belderbos 2 1 Catharina Hospital, Radiation Oncology, Eindhoven, The Netherlands 2 Netherlands Cancer Institute, Radiation Oncology, Amsterdam, The Netherlands 3 Netherlands Cancer Institute, Radiotherapy, Amsterdam, The Netherlands 4 Thomas Jefferson University Hospital, Radiation Oncology, Philadelphia, USA 5 Beaumont Hospital, Radiation Oncology, Royal Oak, USA 6 University of Toronto and Princess Margaret Cancer Center, Radiation Oncology, Toronto, Canada 7 University of Wuerzburg, Radiation Oncology, Wuerzburg, Germany 8 University Hospital Zurich, Radiation Oncology, Zurich, Switzerland Purpose or Objective To report the first results of the prospective multicenter phase I/II VOLUMES trial (NCT01543672) investigating the safety of SBRT for peripheral lung tumors >5 cm. Material and Methods Eligible patients had a peripheral lesion >5 cm (primary tumor or solitary metastasis) and were either inoperable or refused surgery. Patients with 2 tumors in close proximity (50% isodose line coverage of both PTVs, sum diameter >5 cm) were accepted. Radiation pneumonitis (RP) was anticipated to be the dose-limiting toxicity (DLT), which is correlated with the Mean-Lung Dose (MLD) (1). Therefore, an MLD (EQD 2 α/β=3 Gy) escalation was performed. Six risk groups (RG) were defined, increasing the MLD with 3 Gy in each step, ranging from <9 Gy (RG1) to 21-24 Gy (RG6) for the lowest and highest RG respectively. SBRT was delivered with VMAT and on-line image guidance. DLT was monitored by the Time-to-Event Continuous Reassessment Method (TITE-CRM) and defined according to the CTCAE v4. For non-lung toxicity a 3+3 design was used. The primary endpoint was to assess the maximum tolerated MLD with a 20% probability of DLT. Secondary endpoints were locoregional control, overall survival and quality of life. Results Between November 2011 and April 2016 all 30 patients were enrolled, with patient numbers per each RG as follows: RG1:7; RG2:8; RG3:10; RG4:3; RG5:2; RG6:0. Median age was 72 years (range 54-87), 67% was male. Most patients had a WHO score-1 with a median Charlson

co-morbidity index of 2 (range 0-7). Primary NSCLC was diagnosed in 27 patients, of which 19 cT2b and 8 cT3 (7 th TNM). Three patients had lung metastases. Tumors were biopsy proven in 63%. The median GTV and PTV of large tumors (n=22) were 65cc (18-127) and 157cc (49-340) vs. 23cc (1-45) and 78cc (16-132) for 2 tumors (n=8). The most frequent (47%) SBRT schedule was 3x18 Gy. After a median follow-up (FU) of 19 months 3 DLTs were reported: one RP G5 at 8 months (MLD=19.5 Gy), one cavitating lung infection G3 at 6 months (MLD=18 Gy) and one G4 skin ulceration at 22 months. G3 toxicity was scored 5 times in 3 patients: dysphagia, fracture, chest wall pain, anorexia and dyspnea. The predicted maximum tolerated MLD was 21-24 Gy (95% probability interval 0.036-0.304) (Fig 1). One year local control (LC) (Fig 2), regional control (RC), distant control (DC) and disease free survival (DFS) were 96% (95%CI 0.9-1.0), 92% (95%CI 0.8-1.0), 78% (95%CI 0.6-1.0) and 76% (95%CI 0.6-1.0) respectively. Two year LC, RC, DC and DFS were 83% (95%CI 0.7-1.0), 84% (95%CI 0.7-1.0), 68% (95%CI 0.5-1.0) and 49% (95%CI 0.3-0.8) respectively. Overall survival (OS) at 1 and 2 years was 83% (95%CI 0.7-1.0) and 55% (95%CI 0.4-0.9) respectively.

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