ESTRO 36 Abstract Book

S652 ESTRO 36 _______________________________________________________________________________________________

EP-1206 FDG-PET/CT predictive parameters of early response after SABR for lung oligometastases R. Mazzola 1 , N. Giaj Levra 1 , A. Fiorentino 1 , S. Fersino 1 , F. Ricchetti 1 , U. Tebano 1 , D. Aiello 1 , R. Ruggieri 1 , F. Alongi 1 1 Sacro Cuore Don Calabria Cancer Care Center, Radiation Oncology, Negrar-Verona, Italy Purpose or Objective To investigate the role of 18FDG-PET/CT parameters as predictive of early response after Stereotactic Ablative Radiation Therapy (SABR) for oligometastases lung lesions. Material and Methods SABR for lung oligometastases was performed when the following criteria were satisfied: a) controlled primary tumor, b) absence of progressive disease longer than 6 months, c) number of metastatic lesions ≤ 5. The prescribed total dose varied according to the risk-adapted dose prescription with a range of doses between 48-70 Gy in 3-10 fractions. Inclusion criteria of the current retrospective study were: a) lung oligometastases underwent to SABR, b) for each patient presence of 18- FDG-PET/CT pre- and post-SABR for at least two subsequent evaluations, c) Karnofsky performance status > 80, d) life-expectancy > 6 months. The following metabolic parameters were defined semi- quantitatively for each lung lesion: 1) SUV-max, 2) SUV- mean, 3) Metabolic Tumor Volume (MTV), 4) Total Lesional Glycolysis (TLG). Results From January 2012 to November 2015 fifty patients for a total of seventy lung metastatic lesions met the inclusion criteria of the present analysis. Pre-SABR, median SUV- max was 6.5 (range, 4 - 17), median SUV-mean was 3.7 (2.5 - 6.5), median MTV was 2.3 cc (0.2 - 31 cc). For patients with in-field disease progression median TLG was 17.4 (2 - 52.8), for the remaining the median value was 170.6 (0.5 - 171). For pre-SABR SUV-max ≥ 5 a progression/stable metastasis was noted in 88% of cases, while a complete response was observed in 94% of cases for pre-SABR SUV-max < 5 (p < 0.001, Sensitivity = 88%, Specificity = 94%). A pre-SABR SUV-mean < 3.5 was related to complete response at 6 months after SABR (p 0.03, Sensitivity = 31%, Specificity = 34%, AUC = 0.32). In cases of in-field failure, a pre-SABR SUV-max > 8 was related to a higher absolute value increase of SUV-max at 6 months of follow up comparing to pre-SABR SUV-max < 8 (p 0.005). Delta SUV max 3-6 months was +126% for lesions with in- field progression versus -26% for the remaining (p-value 0.002). Delta SUV-mean 3-6 months was +15% for lesions with in-field progression versus for the remaining 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

14.1 months, respectively. At MVA, BED ≥100 and KPS ≥90 emerged as a significant prognostic factors for OS (p = 0.01 and p = 0.001, respectively), and BED ≥100 for PFS (p = 0.02). Conclusion Our findings show that a risk adaptive approach of HT- SBRT based on tumor location is an effective treatment with a mild toxicity profile in medically inoperable patients with lung tumors. No specific pattern of lung injury was demonstrated. EP-1205 The prognostic role of Neutrophil-to- lymphocyte ratio in limited disease small-cell lung cancer L. Käsmann 1 , L. Bolm 1 , L. Motisi 1 , S. Janssen 1 , S.E. Schild 2 , D. Rades 1 1 University of Lübeck, Department of Radiation Oncology, Lubeck, Germany 2 Mayo Clinic, Department of Radiation Oncology, Scottsdale- AZ, USA Purpose or Objective Small cell lung cancer is an aggressive cancer type of neuroendocrine origin. Even patients with limited disease have a poor prognosis of 16-24 months. Standard treatment of these patients is radiochemotherapy with cisplatin and etoposide followed by prophylactic cranial irradiation. Systemic inflammation has been suggested an important prognostic factor for outcome in several types of cancer. In this study, we investigated the impact of systematic inflammation represented by the neutrophil- to-lymphocyte ratio (NLR) at diagnosis in patients with limited disease small-cell lung cancer (LD-SCLC) for outcomes. Material and Methods Data of 65 patients receiving radiochemotherapy for LD- SCLC were analyzed. NLR was obtained from blood samples at diagnosis. NLR plus 12 factors, namely gender, age, ECOG performance score, T-category, N-category, number of pack years, smoking during radiotherapy (RT), respiratory insufficiency prior to RT, haemoglobin levels during RT, EQD2 (<56 Gy vs. ≥56 Gy), concurrent chemotherapy and PCI, were evaluated for local control, metastases-free survival and overall survival. Results The overall survival rates at 12, 24 and 36 months were 71%, 45% and 28%, respectively. Median survival time was 20 months. On univariate analysis of local recurrence, lower T-stage (1-2 vs. 3-4) was associated with improved local control at 36 months (62% vs. 41%, p=0.04). On multivariate analysis, T-stage was an independent factor (p=0.035; HR 1.84 (95% Cl 1.04-3.86)). Improved metastases-free-survival on univariate analyses was found for NLR <4 (p=0.011), ECOG 0-1 (p=0.002), nodal stage N0- 1 (p=0.048), non-smoking during RT (p=0.009), and administration of PCI (p=0.006). On multivariate analysis, a trend for improved metastases-free-survival was observed for NLR <4 (p=0.063; HR 2.19 (95% Cl 0.96-5.06)) and N0-1 (p=0.0623; HR 3.4 (95% Cl 0.95-21.9)). Improved overall survival rates were found for NLR <4 (p=0.001), ECOG 0-1 (p<0.001), non-smoking during RT (p=0.007), no respiratory insufficiency prior to RT (p=0.03) and PCI (p<0.001). On multivariate analysis, NLR <4 (p=0.03; HR 2.05 (95% Cl 1.06-3.95)), ECOG 0-1 (p=0.002; HR 3.41 (95% Cl 1.57-7.36)) and PCI (p=0.015; HR 2.56 (95% Cl 1.21-5.34) were independently associated with improved survival. Conclusion In this study, NLR was an independent prognostic factor for overall survival in patients with LD-SCLC. NLR can help identify patients with poor prognosis and appears an useful prognostic marker in clinical practice. A prospective analysis is warranted to confirm our findings.