ESTRO 37 Abstract book

S764

ESTRO 37

EP-1400 Outcomes According to SRS Dose Prescription for Brain Metastases from Lung Cancer F. Moraes 1 , J. Winter 2 , A. Dasgupta 1 , H. Razie 1 , C. Coolens 2 , Z. Gelareh 3 , P. Kongkham 3 , M. Bernstein 3 , T. Conrad 1 , N. Laperriere 1 , B. Millar 1 , A. Berlin 1 , D. Shultz 1 1 Princess Margaret Cancer Centre, Radiation Medicine Program, Toronto, Canada 2 Princess Margaret Cancer Centre, Medical Physics, Toronto, Canada 3 Princess Margaret Cancer Centre, Neurosurgery, Toronto, Canada Purpose or Objective At our institution, we commonly treat brain metastases (BM) adjacent to critical structures with a reduced marginal dose prescription (DP) to reduce the likelihood of toxicity. We sought to evaluate the impact of DP on local failure (LF) and radionecrosis (RN) for small- to medium-sized BM (≤ 2 cm) from non-small cell lung cancer. Material and Methods A prospective registry of BM patients treated with gamma knife SRS between 2008 and 2016 was reviewed to determine per lesion rates of LF and RN. Each lesion was followed until LF or RN or at last MRI follow-up. Defined criteria were used to differentiate LF from RN. Whole brain irradiation (WBI) was a censoring event. Freedom from LF (FFLF) and RN (FFRN) were calculated using the Kaplan-Meier product-limit method. Log-rank test was used as a univariate analysis to compare potential predictive factors of LF or RN events. Results From 1,465 potential subjects, 345 small- to medium- sized BM from 151 lung cancer patients were evaluated. Median radiographic follow-up was 10.2 months. Median lesion volume and diameter were 0.17 cm 3 , and 0.81 cm, respectively. Median OS was 17 months (95CI 14.9-19.09) with 1 year OS of 69.13% (95CI 62.9-74.4%). The DP for 71 lesions (21%) was 15 Gy, and ≥ 20 Gy (median 21 Gy; 20- 24Gy) for 274(79%). Most lesions were ≤ 1 cm (65%). Median number of SRS courses was 2 (1-4) and 36 patients received salvage WBI. Sixteen lesions (4%) developed LF and 12 (3%) developed RN. Freedom from local failure at 1 year (FFLF) for 15 Gy, and ≥ 20 Gy, was 80%, and 95%, respectively (p<0.05). FFLF for lesions ≤1cm, and >1 cm, was 95%, and 78%, respectively (p<0.01). Freedom from RN at 1-year (FFRN) for DP 15 Gy, and ≥ 20 Gy, was 98%, and 96%, respectively (p=0.3). FFRN for lesions ≤ 1cm, and > 1 cm, was 98%, and 93%, respectively (p<0.05). FFLF and FFRN for lesions ≤1 cm and >1 cm, according to DP, are shown in Table 1 . Conclusion Lesions > 1 cm showed improved FFLF improvement with higher DP, although this trend did not reach statistical significance. Prospective randomized evaluation is urged to define the optimal DP. EP-1401 FDG and FMISO-PET for guided dose escalation with intensity-modulated radiotherapy in lung cancers. S. Thureau 1 , D. Gensanne 1 , N. Pirault 1 , R. Modzelewski 2 , P. Gouel 2 , P. Bohn 2 , S. Hapdey 2 , P. Vera 2 , B. Dubray 1 1 Centre Henri Becquerel - Quantif EA 4108, Radiotherapy, Rouen, France 2 Centre Henri Becquerel - Quantif EA 4108, Nuclear Medecine, Rouen, France Purpose or Objective Radiotherapy is the reference processing for non- resectable locally advanced non-small cell lung cancer (NSCLC). However, effectiveness of radio-chemotherapy (RTCT) is low and the increase of the dose may be deleterious. Positron emission tomography (PET) is a potential implement for optimization in lung

Mean time to INF recurrence was 11.1 months (5-32 months). Looking specifically at NSCLC patients, there was a significant difference in the proportion of INF recurrences in patients with confirmed adenocarcinoma (n=5) compared to those in patients with confirmed squamous cell carcinoma (n=1, Chi-squared= 4.23, p= 0.039). Conclusion Our low INF rate after radical treatment is comparable with other studies. Preponderant INF regional lymph node failure sites included upper para-tracheal; hilar; and sub-carinal. The higher rate of INF recurrence in adenocarcinoma may warrant further investigation into target volume delineation and a consideration of PTV expansion in this subtype. EP-1399 HEmatologic paRaMeters as prEdictive biomarkerS in NSCLC (HERMES-Lung) for metastasis development A. Martino 1 , J. Lenkowicz 1 , G. Mattiucci 1 , A. Petrone 1 , A. Piras 1 , D. Smaniotto 1 , A. Alitto 1 , C. Mazzarella 1 , G. Palazzoni 1 , M. Congedo 2 , M. Chiappetta 2 , S. Margaritora 2 , V. Valentini 1 , G. Mantini 1 1 Policlinico Universitario Agostino Gemelli- Catholic University, Gemelli ART-Advanced Radiation Therapy, Roma, Italy 2 Policlinico Universitario Agostino Gemelli- Catholic University, Thoracic Surgery Unit, Roma, Italy Purpose or Objective Systemic inflammatory response has been confirmed to have prognostic value in several types of cancer, including lung cancer. This study was aimed to investigate the usefulness of circulating hematologic parameters in predicting distant metastasis development in patients with locally advanced non-small cell lung cancer (NSCLC). Material and Methods We retrospectively reviewed the medical records of 53 patients (38 (71.7%) male, median age 67) with stage IIIA/IIIB NSCLC, treated between March 2009 and October 2016. All patients underwent multimodality approach, including surgery. Peripheral complete blood count were collected at baseline and after two cycles of induction treatment: absolute neutrophil count (ANC), absolute platelet count (APC), absolute lymphocyte count (ALC), Neutrophil-to-Lymphocyte Ratio (NLR) and Platelet-to- Lymphocyte Ratio (PLR). Patients were dichotomized according to the median value for each parameter. OS was estimated using the Kaplan-Meier method and logistic regression model was used for multivariable analysis. Results In the overall population, median OS (mOS) e median distant metastasis free survival (mDMFS) were respectively 14 and 13 months. Kaplan-Meier survival analysis suggested that patients who experienced baseline high-APC, in comparison with low-APC, showed significant reduction in OS (p=0.02) and those with high- ANC, in comparison with low-ANC, showed only marginally reduction in OS (p=0.05). Using a logistic regression model to predict distant metastasis development within 12 months from diagnosis we observed that increasing ANC (p=0.023) and increasing PLR (p=0.012) at baseline were significant predictive markers [AUC Area under the curve: 0.8581; 95% CI: 0.7537-0.9625 (DeLong)]. Conclusion Neutrophilia and elevated PLR might be potential predictive biomarkers for distant metastasis development in NSCLC. These findings allow to select patients, according to different risk group, for intensified local treatment and personalized therapy. The predictive value should be prospectively validated.