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D.S. Møller
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MINI 07 - ChemoRT and Translational Science (ID 110)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Treatment of Locoregional Disease – NSCLC
- Presentations: 1
- Moderators:D. Raben, B. Kavanagh
- Coordinates: 9/07/2015, 16:45 - 18:15, 201+203
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MINI07.03 - The NARLAL2 Phase III Trial: Heterogeneous FDG-Guided Dose Escalation of Advanced NSCLC. A Clinical Trial by the Danish Lung Cancer Group (ID 2248)
16:55 - 17:00 | Author(s): D.S. Møller
- Abstract
- Presentation
Background:
Locally advanced lung cancer lacks effective treatment options and requires aggressive radiotherapy (RT) with higher doses. In the light of RTOG 0617, multi-center dose escalation trials should avoid increasing organ at risk (OAR) toxicity and require strict quality assurance (QA). Exploiting the predictive value of FDG-PET, sub-volumes can be dose escalated, and by implementing image-guided adaptive RT, the total treatment volume (PTV) can be reduced. Incorporating these elements, the randomized multicenter trial NARLAL2 aims at increasing loco-regional control at 30 months without increasing major toxicity.
Methods:
Figure 1 In the standard arm, the PTV is treated with a homogenous dose of 66 Gy/33 fractions. In the experimental arm, the dose is heterogeneously escalated to the FDG-PET avid volumes, with mean doses up to 95 Gy/33 fractions and 74 Gy/33 fractions to the escalated volumes in the tumor and malignant lymph nodes, respectively. The escalation dose will be limited in favor of OAR constraints. A standard and an experimental treatment plan with similar mean lung doses of maximum 20 Gy are made for each patient prior to randomization. Quality Assurance: FDG-PET scans of a standard phantom (NEMA) and PET signal processing software from all centers were compared and acceptable agreement achieved. Multicenter delineation of OARs was performed and consensus achieved. Treatment planning and adaptive strategy consensus were based on a study including five patients with repeated CT-scans, requiring several steps before the achievable level of dose escalation and the number of patients needed in the trial could be defined. Daily online tumor set-up and adaptive strategies were mandatory. A QA committee for evaluation of RT plans and treatments and a central committee for evaluation of all non-biopsy-verified recurrences were established.
Results:
A mean dose of 91,9 Gy to the FDG-PET avid part of the tumor and 80 Gy to the clinical target volume was achieved in the planning study, corresponding to 16% estimated increase in locoregional control at 30 months. Assuming a loco-regional control of 56% at 30 months in the standard arm, a total of 330 patients were needed in order to resolve this effect with a power of 80% (95% significance level). Recalculation of escalated plans on CT-scans acquired at fraction 20 revealed an increase in OAR doses of 4-7Gy for two of five patients, endorsing the need for adaptive strategies.
Conclusion:
A dose escalation trial with strict QA has been set up. Patient enrollment started January 2015.
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ORAL 36 - Translational Science/Radiation (ID 151)
- Event: WCLC 2015
- Type: Oral Session
- Track: Treatment of Locoregional Disease – NSCLC
- Presentations: 1
- Moderators:E. Vokes, B. Kavanagh
- Coordinates: 9/09/2015, 16:45 - 18:15, Mile High Ballroom 2c-3c
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ORAL36.07 - Results of a National Test Run of Treatment Plans for the Standard Arm of a Dose Escalation Trial for Locally Advanced NSCLC (ID 1766)
17:50 - 18:01 | Author(s): D.S. Møller
- Abstract
- Presentation
Background:
A national quality assurance program was conducted in order to compare standard radiation treatment plans for locally advanced non-small cell lung cancer (NSCLC) patients in Denmark.
Methods:
The five participating centres represented 71% of all radiotherapy centres in Denmark. They were provided with the CT images and delineations of GTV, CTV, PTV and organs at risks for five different NSCLC patients. Each centre created treatment plans based on the following optimization objectives: required dose distribution for target coverage 95%-107% of the prescribed dose of 66Gy/33fr to at least 95% of the PTV volume (90% for volume located in lung tissue); constraints for organs at risks D(max) < 50Gy to the spinal cord, D(max) < 70Gy to the oesophagus, V50 < 20% to the heart, V20 < 35% and D(mean) < 20Gy for the total lung volume (excluding the GTV). The treatment planning was done in accordance with the local centre practice; i.e. choice of IMRT versus VMAT, coplanar vs. non-coplanar technique, feasible functionalities for treatment planning optimisation (mean value versus different points at the DVH curve), and any additional local dose constraints (e.g. D(max) < 45Gy to spinal cord and/or V5 < 60% to the total lung volume). Finally, all treatment plans were collected and analysed cooperatively.
Results:
All objectives for target coverage and organs at risk were met. There was a wide variability in the dose volume histograms (DVHs) for some of the organs at risk, especially the lungs. This is illustrated in the figure, where the lung DVH from seven different treatment plans, created for the same patient by the five participating centres, is shown. The lung DVHs are overlapping around 20Gy, as all centres had a dose constraint on V20. Some centres had an additional local dose constraint on V5, which resulted in decreased doses to the lungs and increased doses to the mediastinal structures compared with centres that had no dose constraints on V5 for the lungs. Figure 1
Conclusion:
Differences in the dose distribution to the organs at risk can have an impact on treatment morbidity (e.g. pneumonitis, oesophagitis). These differences were seen for standard treatment plans, which are often used in multicentre clinical trials as the baseline compared to an experimental arm, where such differences can be even more pronounced. It is highly recommended to perform test runs across centres prior to entering clinical trials in order to uncover differences as the ones presented.
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