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C. Pöttgen
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MA13 - Modern Technologies and Biological Factors in Radiotherapy (ID 395)
- Event: WCLC 2016
- Type: Mini Oral Session
- Track: Radiotherapy
- Presentations: 1
- Moderators:M. Thomas, P. Mitchell
- Coordinates: 12/06/2016, 16:00 - 17:30, Stolz 1
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MA13.04 - Discussant for MA13.01, MA13.02, MA13.03 (ID 7088)
16:00 - 17:30 | Author(s): C. Pöttgen
- Abstract
- Presentation
Abstract not provided
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MTE06 - Radiotherapy Techniques in Lung Cancer (Ticketed Session) (ID 300)
- Event: WCLC 2016
- Type: Meet the Expert Session (Ticketed Session)
- Track: Radiotherapy
- Presentations: 1
- Moderators:
- Coordinates: 12/05/2016, 07:30 - 08:30, Strauss 3
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MTE06.02 - Radiotherapy Techniques in Lung Cancer (ID 6549)
07:30 - 08:30 | Author(s): C. Pöttgen
- Abstract
- Presentation
Abstract:
Dose escalation with conventional fractionation and concurrent platin-based chemotherapy within the RTOG 0617 trial has failed to show a survival benefit. Proton therapy has failed to show a reduction in radiation pneumonitis in comparison to intensity modulated photon radiotherapy at the same total dose according to the NCT 00915005 trial. Randomized trials for comparison of IMRT and 3D conformal radiotherapy are lacking. While randomized trials conducted so far failed to show an increment in survival by newer radiotherapy concepts on one hand, the old standard of giving 60 Gy with conventional fractionation and concurrent chemotherapy consolidated on the other. So where does the hope come from that technological advances in radiotherapy lead to an improved survival in locally advanced lung cancer, if not from randomized trials? It comes from many small precious components that can lead to an increase of loco-regional control by radiotherapy in locally advanced NSCLC, the primary goal of radiotherapy. First of all, the determination of tumor spread has been substantially improved by the introduction of FDG-PET/CT, by systematic mediastinal evaluation with EBUS-TBNA, and by brain MRI. The determination of tumor position during irradiation has been improved by stereoscopic KV imaging during irradiation or real-time magnetic resonance imaging and therefore tumor targeting can be optimized. Volumetric modulated arc therapy can deliver conformal dose distributions within a breath hold of 20 s. With hyperfractionated acceleration and concurrent chemotherapy, high biologically effective doses can be given for patients with locally advanced NSCLC resulting in similar survival and local control rates than with trimodality treatment. Integrated boost radiotherapy controlling dose gradients form gross tumor volume towards organs at risk as the contra-lateral bronchial wall or the esophagus has become feasible and is tested within prospective trials. Immunotherapy and molecular targeted therapies are upcoming as combination partners with radiotherapy in selected tumors. Proper patient selection criteria resulted long term survival as high as 30-45% in multicenter prospective trials in locally advanced NSCLC. These advantages have to be bundled into new radiotherapeutic concepts and tested against the standard of conventional fractionated radiotherapy up to 60 Gy and simultaneous chemotherapy in future well designed randomized trials.
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SC01 - Staging Before and After Induction Therapy for N2 Disease (ID 325)
- Event: WCLC 2016
- Type: Science Session
- Track: Radiology/Staging/Screening
- Presentations: 1
- Moderators:G. Mostbeck, E. Fadel
- Coordinates: 12/05/2016, 11:00 - 12:30, Lehar 3-4
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SC01.02 - PET-CT for Response Assessment During Induction Therapy of N2 NSCLC (ID 6599)
11:00 - 12:30 | Author(s): C. Pöttgen
- Abstract
Abstract:
Approximately 30% of patients with non-small cell lung cancer (NSCLC) are found to have locally advanced stage III tumours at initial diagnosis. For these patients the curative therapeutic options include definitive high-dose radiotherapy with concurrent chemotherapy or, alternatively, induction treatment followed by surgery. Preoperative chemotherapy or combined radiochemotherapy protocols followed by resection result in cure rates of 25-35 percent at 3 years for locally advanced NSCLC. However, surgical resection in patients with stage IIIa N2 remains an issue of controversy depending on the extent of lymph node involvement. Neoadjuvant chemo- or radiochemotherapy is being used to reduce disease burden in the mediastinum before surgery since patients who are downstaged via neoadjuvant therapy and then undergo resection experience a significantly longer 5-year survival of 40% to 50% than those who are found to have residual N2 disease at the time of surgery. Thus, identification of patients who are N2 negative after completion of their neoadjuvant therapy is a critical component for patient selection for thoracotomy. However, clinical restaging in these patients often is challenging. Endoscopic ultrasound guided biopsies (EUS/EBUS-FNA) have increasingly become available and are currently preferred procedures for staging and restaging before surgery due to their high diagnostic accuracy.(1) Serial PET-CT imaging captures anatomical changes and additionally offers semiquantitative information about morphometric and metabolic tissue changes during induction treatment. Issues of PET-CT performance and quality assurance concerning standardization have been clarified during recent years and the validity of repeated measurements has been approved.(2) Successful induction treatment regimes have been frequently found to reduce 18F-FDG uptake and thus PET-CT allows to assess the therapeutic response. Reduction in FDG-uptake of mediastinal lymph nodes after induction therapy has been shown to correlate well with histopathologic response (3), while postinduction PET avidity taken alone was not consistently found to be associated with pathological N2 involvement (4). In the direct comparison of EUS-FNA with PET-CT for restaging after induction chemoradiotherapy, concordance between findings of restaging EUS-FNA and metabolic response of lymph node metastases was observed in 63% patients treated within a prospective study but the diagnostic accuracy of PET-CT was limited.(5) Nevertheless, serial FDG-uptake measurements seem to provide prognostic information during induction therapy. Data collected in prospective trials suggest that a decrease in SUV~max~ between 45% to 60% optimally separates between responders and non-responders (6-9). In a recent large retrospective analysis, a decrease in SUV~max~ greater than 60% in the involved mediastinal nodes was the best predictor of overall survival, better than changes seen in the primary tumour site. (10) An analysis of a randomized trial in potentially resectable stage III NSCLC of induction treatment (including a hyperfractionated accelerated radiotherapy phase) and definitive radiochemotherapy compared with induction treatment followed by surgery confirmed that as early as after two cycles of cisplatin-based induction chemotherapy percentage of SUV~max~ remaining represents a significant prognostic parameter.(9) PET-response was of higher importance than all other clinical factors. Cut-off levels between 0.45 and 0.55 were predictive for freedom from extracerebral progression in all randomized patients. No important differences in the predictive value were observed comparing resection versus definitive radiochemotherapy. PET-response was closely related to extracerebral distant metastases but not to local recurrences, independent of treatment. One might conclude that less PET-responsive tumors are successfully controlled by intensified hyperfractionated accelerated radiochemotherapy or neoadjuvant radiochemotherapy and resection at loco-regional sites so that the highest risk of relapse remains at extracerebral distant sites. Therefore, a selection or intensification of the local therapy according to SUV-decrease is not warranted by these data. Functional imaging has not yet been fully established for treatment guidance but prospective evaluation is underway. In the group of poor-responding patients, treatment intensification by independent systemic options such as targeted therapy or immunomodulating therapy may become emerging new treatment options within clinical trials. References: 1) De Leyn EJCTS 2014, 2) Young, EJC 1999, 3) Pöttgen CCR 2006, 4) Ripley JTCS 2016, 5) Stigt, Lung Cancer 2009, 6) Hoekstra, JCO 2005, 7) Eschmann, Lung Cancer 2007, 8) Dooms, JCO 2008, 9) Pöttgen, JCO 2016, 10) Barnett ATS 2016
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SH06 - WCLC 2016 Scientific Highlights - Radiotherpay, Palliative Care, Regional Aspects (ID 488)
- Event: WCLC 2016
- Type: Scientific Highlights
- Track: Radiotherapy
- Presentations: 1
- Moderators:
- Coordinates: 12/07/2016, 07:30 - 08:30, Hall C7
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SH06.01 - Radiotherapy (ID 7132)
07:30 - 08:30 | Author(s): C. Pöttgen
- Abstract
- Presentation
Abstract not provided
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