ESTRO 37 Abstract book

S289

ESTRO 37

[3] Eustace. Clin Cancer Res 2013;19:4879–88. [4] Yang. Clin Cancer Res 2017;23:4761–8. [5] Overgaard. Lancet Oncol 2005;6:757–64. [6] Nijkamp. Eur J Cancer 2013;49:3202–9. [7] Rademakers. Radiother Oncol 2013;108:517–2 [8] Rademakers. Head Neck 2015;37:171–6 [9] Le. Clin Cancer Res 2012;18:1798–807. [10] Hunter. Cancer Res 2015;75:4211–23. [11] Eustace. Radiother Oncol 2013;108:40–7.

IMRT and escalate the dose while the OTT is not prolonged. Another strategy is to improve patient selection. Using circulating serum -microRNA signature and clinical factors, a dose response score has been reported that identified a subset of patients with an overall survival benefit from high-dose radiotherapy [3]. A mathematical model used to analyze 23 early stage patient cohorts[4] concluded that hypofractionation regimens overcome hypoxia (and cell-cycle radiosensitivity variations) by the pure impact of high doses per fraction. Lower dose-per-fraction regimens allow for reoxygenation and corresponding sensitization, but lose effectiveness due to proliferation. Conclusion; Effective consolidation therapy after CCRT has been developed and locoregional control is more important than ever. Dose-escalation should be executed in a patient-specific manner with preferably hypofractionated regimens. The combination of fractionated RT and SBRT might be a smart strategy compared to fractionated dose escalation studies. High doses to the mediastinal structures can be avoided using IMRT. [1] Scott J et al. Durvalumab after Chemoradiotherapy in Stage III Non–Small-Cell Lung Cancer. N Engl J Med 2017; 377:1919-1929 [2] Randomized Trial of SABR vs Conventional Radiotherapy for Inoperable Stage I Non-Small Cell Lung Cancer: TROG 09.02 (CHISEL) [3] Sun Y et al. Serum MicroRNA Signature Predicts Response to High-Dose Radiotehrapy in Locally Advanced Non-Small-Cell Lung cancer. Int J Radiat Oncol Biol Phys. 2017 Sep 4 [4] Jeong J et al. Clin Cancer Res. Modeling the Cellular Response of Lung Cancer to Radiation Therapy for a Broad Range of Fractionation Schedules. 2017 Sep 15;23(18):5469-5479. SP-0553 What’s new in the management of high risk prostate cancer patients in 2018: the role of Imaging R. Renard Penna 1 , P. Maksud 2 1 Institut Curie Ensemble Hospitalier service formation, Imagery, Paris cedex 05, France 2 Pitié salpétrière, Nuclear medecine, paris, France Abstract text Objetives This course will identify the relevance of MRI and modern imaging concepts for the management of high risk prostate cancer We will explore the impact of prostate MRI, targeted biopsies and biomarkers for optimizing detection and characterization of high risk prostate cancers, We also present the most current information regarding the performance of prostate MRI for local staging and the impact for treatment. We will discuss about modern imaging concepts for the preoperative lymph node staging (PET CT and PET MR) and new tracers as C11 choline, F18 fluciclovine, and Prostate Specific Membrane Antigen (PSMA) labeled tests. Learning objectives: · Impact of prostate MRI and targeted Biopsies in characterization of high risk prostate cancer· Optimal staging of patients with high risk prostate cancer by understanding the performance of prostate MRI for evaluation of extra-capsular extension or seminal vesicles involvement· Apply the most modern imaging concepts for lymph node staging. · Impact of PET/CT and PET/MRI in detection of micro- metastases· Role of 68GA-PSMA, 18F-PSMA-1007 and new tracers in improving staging of high risk prostate cancer Symposium: What’s new in the management of high risk prostate cancer patients in 2018?

Debate: This house believes that treatment intensification in stage III is a dream rather than a reality?

SP-0551 For the motion C. Faivre-Finn Institute of Cancer Sciences, Manchester, the United Kingdom

Abstract not received

SP-0552 Against the motion: Treatment intensification in stage III NSCLC is a dream rather than a reality? J. Belderbos 1 1 Netherlands Cancer Institute, Radiation Oncology, Amsterdam, The Netherlands Abstract text While new systemic treatment options for stage III non- small-cell lung cancer (NSCLC) patients are being developed, locoregional control remains essential. PACIFIC is the first phase III trial [1] that tested an immune checkpoint inhibitor (durvalumab) as consolidation therapy in patients with stage III NSCLC who had not progressed following concurrent chemoradiation (CCRT). Durvalumab decreased the probability of disease progression with 48%. With this improved systemic control probability in NSCLC patients, the locoregional control rates will even be more important, and treatment intensification is crucial. Efforts to improve control of locally-advanced NSCLC by escalating radiation dose while increasing the overall treatment time (OTT) in unselected patients however, have been unsuccessful. Several new techniques have recently been developed to either select patients and/or tumor sub-volumes that might benefit from dose escalation. Treatment techniques to deliver IMRT are widely available nowadays, and IMRT has been proven to reduce the chance to develop normal tissue toxicity (heart, esophagus) and alow dose escalation. Many studies have identified the tumor volume to be a significant predictor for local control. The primary tumor is often more voluminous than the involved lymph nodes and IMRT techniques help us to deliver inhomogene dose distributions.The recently reported TROG 09.02 trial CHISEL [2] showed improved freedom from local failure for SBRT versus conventional fractionation in patients with inoperable peripheral stage I NSCLC. SBRT (54 Gy in 3, or 48 Gy in 4 fractions) resulted in superior freedom from local failure and was associated with an improvement in overall survival compared to fractionated RT (66 Gy in 33 fractions or 50 Gy in 20 fractions). Several studies reported feasibility and tolerability of sequential SBRT after CCRT in locally advanced NSCLC. The smaller margins generally used in SBRT may even decrease toxicity. Another strategy is boosting a biological defined tumor sub-volume on the pre- treatment FDG-PET scan. This has been pursued in the PET-Boost trial which is currently being analyzed. Defining a tumor sub-volume during treatment, using FDG-PET scan was subject of several trials. All these designs have in common that they deliver individualized