ESTRO 36 Abstract Book

S647 ESTRO 36 2017 _______________________________________________________________________________________________

metastases (p-value 0.008). Finally, 86% of patients with local failure had distant progression versus only 19% in cases without local failure (p = 0.004). Conclusion According to current findings, pre-SABR SUV max and mean seem to predict early response in lung SABR for oligometastases. EP-1207 Outcomes and prognostic factors in solitary brain metastasis from small cell lung cancer D. Bernhardt 1 , S. Adeberg 1 , F. Bozorgmehr 2 , J. Kappes 3 , J. Hoerner-Rieber 1 , L. Koenig 1 , J. Debus 1 , M. Thomas 2 , A. Unterberg 4 , F. Herth 3 , C.P. Heussel 5 , M. Steins 2 , S. Rieken 1 1 University Hospital of Heidelberg, Department of Radiation Oncology, Heidelberg, Germany 2 University Hospital of Heidelberg, Department of Thoracic Oncology- Thoraxklinik- Translational Lung Research Centre Heidelberg TLRC-H, Heidelberg, Germany 3 University Hospital of Heidelberg, Department of Pneumology- Thoraxklinik, Heidelberg, Germany 4 University Hospital of Heidelberg, Department of Neurosurgery, Heidelberg, Germany 5 University Hospital of Heidelberg, Diagnostic and Interventional Radiology with Nuclear Medicine- Thoraxklinik, Heidelberg, Germany Purpose or Objective Whole brain radiation therapy (WBRT) was historically the standard of care for patients with brain metastases (BM) from small cell lung cancer (SCLC). Even though, for patients from other solid tumours, locally ablative treatments are standard of care for patients with 1-4 BM. The objective of this analysis was to find prognostic factors influencing overall survival (OS) and progression- free survival (nPFS) in SCLC patients with solitary BM (SBM) treated with WBRT. Material and Methods We identified 52 patients in our cancer center database that had histologically confirmed SCLC and contrast enhanced magnet resonance imaging (MRI) or computed tomography (CT) confirmed SBM between 2006 and 2015. Kaplan–Meier survival analysis was performed for survival analyses. For comparison of survival curves, Log-rank (Mantel-Cox) test was used. Univariate Cox proportional- hazards ratios (HRs) were used to assess the influence of cofactors on OS and nPFS. Results The median OS after WBRT was 5 months and the median nPFS after WBRT was 16 months. Patients who received surgery prior to WBRT had a significantly longer median OS of 19 months compared to 5 months in the group receiving only WBRT (p=0.03; HR 2.24; 95 % CI 1.06-4.73). Patients with synchronous disease had a significantly longer OS compared to patients with metachronous BM (6 months vs. 3 months, p=0.005; HR 0.27; 95 % CI 0.11-0.68). Univariate analysis for OS did show a statistically significant effect for metachronous disease (HR 2.84; 95% CI 1.26-6.38; p=0.012), initial response to first-line chemotherapy (HR 0.54; 95% CI 0.30-0.97; p=0.04) and surgical resection (HR 0.25; 95 % CI 0.07-0.83; p=0.024). NPFS was significantly affected by metachronous disease in univariate analysis (HR 14.84; 95% CI 1.46-150.07; p=0.02). Conclusion This analysis revealed that surgery followed by WBRT leads to an improved OS in patients with SBM in SCLC. Further, synchronous disease and response to initial chemotherapy appeared to be major prognostic factors. We propose that locally ablative treatments in combination with WBRT for SBM in SCLC should be considered for therapy. Surgery followed by WBRT should be favored in patients with unknown primary, when pathologic confirmation is required or in patients with large single brain metastasis causing mass effect. The value of WBRT, SRS or surgery

alone or the combination for patients with limited number of BM in SCLC must be evaluated in further prospective clinical trials. EP-1208 Concomitant chemoradiotherapy followed by stereotactic ablative boost in non small cell lung cancer J. Doyen 1 , M. Poudenx 2 , J. Gal 3 , J. Otto 2 , J. Mouroux 4 , B. Padovani 5 , A. Leysalle 1 , C. Guerder 6 , E. Chamorey 3 , P. Bondiau 1 1 Centre Antoine Lacassagne, Radiation Oncology, Nice, France 2 Centre Antoine Lacassagne, Medical Oncology, Nice, France 3 Centre Antoine Lacassagne, Statistics, Nice, France 4 CHU Teaching hospital, Thoracic surgery, Nice, France 5 CHU Teaching hospital, Radiology, Nice, France 6 Hôpital de la Croix Rouge, Radiation Oncology, Toulon, France Purpose or Objective The randomized phase III RTOG 7301 trial failed to demonstrate a survival advantage by increasing radiation dose until 74 Gy in locally advanced non small cell lung cancer (NSCLC) treated by concomitant chemoradiotherapy (CRT) and found that mean dose to the heart correlated independently with overall survival (OS). By increasing the dose to the tumor with stereotactic ablative radiotherapy (SABR) one could lead to a greater dose to the target while decreasing the dose to the heart and could improve outcome. A phase I trial was conducted to firstly demonstrate feasibility of this strategy. Material and Methods After 2 induction cycles with cisplatinum (75 mg/m²) and docetaxel (75 mg/m²) CRT used the same regimen (25 mg/m²) in a weekly basis and delivered 46 Gy in 23 sessions; then 3 consecutive fractions of 7 Gy were given with SABR technique with increasing of 1 Gy per session for next dose level (6 dose level; dose escalation with TITE-CRM method). Patients were eligible for the treatment if target volume after 46 Gy was < 6 cm. Results Twenty-six patients (pts) were treated between March 2010 and June 2015; number of pts for dose level 1, 2, 3, 4, 5 and 6 were respectively of 3, 4, 3, 3, 9 and 4. Median age was of 65.4 years (46-81) with 7 female, 19 male, 1 stage I, 1 stage IIB, 14 stage IIIA, 7 stage IIIB and 3 stage IV disease (oligometastatic). With a median follow-up of 37.1 months (1.7-60.7), limiting toxicities (grade 3 to 5) were as follow: G4 oesophagitis (fistula) at dose level 5; grade 5 (hemoptysis) at dose level 6. Patients mainly presented with grade 1-2 asthenia (n=12) or alveolitis (n=9). There were one complete response (3.8%), 17 partial responses (65.4%) and 7 stabilizations (26.9%). The 2-years local control, metastasis-free survival and overall survival were respectively of 70.3%, 44.5% and 50.8%. Conclusion The maximal tolerated dose was 3 X 11 Gy after 46 Gy (Biological Effective Dose: 115.3 Gy) and could be tested in a phase II trial. EP-1209 SBRT for lung metastases: retrospective analyses of tumor control and toxicity with a lower BED. Y. Crempe 1 , I.P. barbosa 1 , C.D.O. Rodrigues 1 , E. Gil 1 , P.H. Zanuncio 1 , P.L. Moraes 1 , l. Fagundes 1 , R. Ferrigno 1 1 hospital beneficencia portuguesa de sao paulo, radiation oncology, sao paulo, brazil Purpose or Objective Many fractionations have been effective on tumor control of primary lung cancer or metastatic lung lesions, most with BED 10 > 100Gy 10 . The aim of this series is to test safety and effectivity of a dose fractionation with a lower BED in the treatment of lung metastatic disease. Material and Methods