Abstract Book

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ESTRO 37

as well as between the 3D movements and Δdose are listed in Table 2 (p<0.01). The 3D movement shows stronger correlations with the Δdose (0.74-0.80) than with Δvolume (0.48-0.62).

for pts treated without SIB and 10.9 (1.7-78.8) months with SIB. One patient, treated with SIB, was alive at the last follow up (October 2017), 78.8 months after the end of HTT. Ten pts died within 3 months of the beginning of HTT. BTV volume ≥ 473 cc was the only predictor of early death: 60,8% of pts lived more than 10 months, 31.4% more than 20 months, 11.8% more than 30 months and 5.9% more than 50 months. Third and 4th stage pts with BTV volume ≤ 204.6 cc treated with SIB had a better survival (20.4 vs 9.2 months, p= 0.015). One patient died three weeks after the end of therapy, with fever and worsening dyspnea, despite the antibiotics and oxygen therapy. Three other G2 and 1 G3 acute pneumonitis were registered. Two G2 and 7 G3 late pneumonitis were registered, 3 with limited duration of oxygen therapy prescription. One patient, with type 2 Diabetes, died with CT evidence of bilateral actinic pneumonia and without progressive disease, 6.9 months after the end of HTT. BTV ≤ 204.6 cc was predictive of late G≥2 radiation pneumonitis (pulmonary function not yet compromised by MPM). Conclusion With salvage FDG-PET/CT guided helical IG- IMRT in pts with progressive MPM the median survival was similar to those obtained in series using extrapleural pneumonectomy or P/D and adjuvant chemotherapy and radiotherapy (Rosenzweig et al, Int J Radiat Oncol Biol 2011, 83:1278). G≥2 late pneumonitis rate and fatal toxicities are similar to other published series and depend on BTV volume. Results suggest that RT may be delayed, as a salvage, without losing survival, but postponing toxicity. EP-1391 EGFR/ALK Mutations in Stage III Non-small Cell Lung Cancer Patients Received Chemoradiotherapy S.F. Nyaw 1 , W.Y. Tin 2 , S.H. Lo 2 , Y. Tung 2 1 Tuen Mun Hospital, Department of Clinical Oncology, New Territories, Hong Kong SAR China 2 Tuen Mun Hospital, Department of Clinical Oncology, Hong Kong, Hong Kong SAR China Purpose or Objective EGFR and ALK mutation are biomarkers predictive of favorable outcomes in metastatic non-small cell lung cancer (NSCLC). Its prognostic value in stage III NSCLC is less clear. The objective of this study is to study the association of EGFR and ALK mutations with clinical outcome in stage III NSCLC patients treated with concurrent chemoradiotherapy. Material and Methods 98 patients with stage III non-small cell lung cancer who received concurrent chemoradiotherapy from January 2008 to March 2017 were retrospectively identified. Activated EGFR and ALK mutations were detected in 20 and 4 patients respectively. Kaplan-Meier method was used to conduct the progression-free survival (PFS) and overall survival (OS) analyses. Results 55 (56%) patients had stage IIIA and 43(44%) patients had stage IIIB disease. Majority (76%) of patients received radiation dose of 60Gy (range 50-66Gy). The most common histology was adenocarcinoma (54%) followed by squamous cell carcinoma (28%). The median follow up time was 66 months. The median progression-free survival (PFS) was 13.3 months and the median overall survival (OS) was 29.3 months. Among the 24 patients with activated EGFR mutation, 21(88%) of them had disease progression. 95% (20/21) of them developed distant metastasis as the first site of disease progression. All patients subsequently received EGFR or ALK targeted therapies upon disease progression. In patients with EGFR/ALK mutations, the 2-year progress-free survival probability was 25% and the 5-year overall survival probability was 13%. Among patients with

Conclusion According to the results, using respiratory gating for lung SBRT enables significant dose reductions of lung tissue as well in inspiration as in expiration. However, it is not possible to conclude which phase is better, because there is no significant difference. There are significant correlations between the Δvolume or the 3D movement of the tumors and the dose reduction of the lung. A strong dose reduction is awaited for tumors whose PTVs are highly minimized through inspiratory or expiratory gating windows. As well as for tumors with a large 3D movement. Our findings show that tumors located close to the cranial part of the heart benefit from an expiratory and those located caudal from an inspiratory gating window. Individual testing of the craniocaudal position in relation to the heart is recommended. EP-1390 Salvage (postponed) hypofractionated tomotherapy for progressive MPM in patients with intact lungs A. Fodor 1 , S. Broggi 2 , E. Incerti 3 , I. Dell'Oca 1 , C. Fiorino 2 , A.M. Samanes Gajate 3 , P. Passoni 1 , M. Pasetti 1 , M.G. Cattaneo 2 , L. Gianolli 3 , R. Calandrino 2 , M. Picchio 3 , N.G. Di Muzio 1 1 San Raffaele Scientific Institute, Department of Radiotherapy, Milano, Italy 2 San Raffaele Scientific Institute, Medical Physics, Milano, Italy 3 San Raffaele Scientific Institute, Department of Nuclear Medicine, Milano, Italy Purpose or Objective Adjuvant IMRT after Pleurectomy/Decortication(P/D), in pts with intact lungs, is to be considered according NCCN guidelines. The aim of this study was to present the outcome of our protocol of salvage moderately hypofractionated tomotherapy (HTT) with/without simultaneous integrated boost (SIB) on FDG-PET positive areas (BTV), for pts with progressive Malignant Pleural Mesothelioma after previous treatments (chemotherapy+/- surgery), and intact lungs Material and Methods From May 2006- April 2014, 51 pts (41 men and 10 women, left pleura: 25, right: 26) with median age 68.8 (38.6-82.0) years, were treated. Histology: epithelioid in 43, sarcomatoid in 8 pts. Initial stage was: I -11 pts, II -14 pts, III -17 pts and IV -9 pts. Chemotherapy up to 6 cycles was prescribed for 33 pts, and for 13 more than 6 cycles. Eighteen pts had P/D and 33 talc pleurodhesis. A total dose of 56 Gy/ 25 fr to the whole pleura was delivered to all pts, with SIB to 62.5 Gy on PET positive volumes in 38 pts. V5, 10 and 20 of contralateral lung were reduced as low as possible, resulting in a median value for D mean <6.9 Gy. Results Median survival from diagnosis was 25.8 (8.4-99.0) months: 5.9 (1.2-50.5) months from the beginning of HTT