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Jose Belderbos
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P1.17 - Treatment of Locoregional Disease - NSCLC (Not CME Accredited Session) (ID 949)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/24/2018, 16:45 - 18:00, Exhibit Hall
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P1.17-07 - The Prognostic Value of Volumetric Changes of the GTV Measured on CBCT During Radiotherapy for CCRT in NSCLC Patients (ID 13159)
16:45 - 18:00 | Presenting Author(s): Jose Belderbos
- Abstract
Background
To pursue personalized cancer care, it is important to determine tumor response during treatment and associate these with outcomes. Previously published literature reported that adenocarcinoma and squamous cell carcinoma have different treatment response and outcome. Therefore, the aim of this study is to examine the prognostic value of volumetric changes of the primary tumor measured on Cone Beam-CT (CBCT) during radiotherapy for locally advanced NSCLC patients treated with concurrent chemoradiation (CCRT).
a9ded1e5ce5d75814730bb4caaf49419 Method
394 NSCLC-patients treated with CCRT between 2007-2013 were included. To determine GTV during treatment, deformable image registration of the planning-CT to all CBCTs was performed. To assess the association of volumetric changes of the gross tumor volume (GTV) with overall survival (OS), progression free survival (PFS) and local regional control (LRC), multivariate cox regression analyses were performed, accounting for potential confounders. Furthermore, the entire group was stratified based on adenocarcinoma and non-adenocarcinoma and an additional log rank and multivariate cox regression analysis based on pathology was performed.
4c3880bb027f159e801041b1021e88e8 Result
In patients with adenocarcinoma, GTV reduction during CCRT was significantly associated with worse OS (HR=1.55, Figure 1). GTV reduction was not significantly associated with PFS and LRC in either subgroup. For the entire group no significant association was found between GTV volume change and OS, PFS or LRC.
8eea62084ca7e541d918e823422bd82e Conclusion
Surprisingly, no associations between GTV changes and outcomes were found for the entire treatment group. In patients with adenocarcinoma, GTV changes during concurrent chemoradiaton measured on CBCT were a significant predictor for OS.
6f8b794f3246b0c1e1780bb4d4d5dc53
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P3.01 - Advanced NSCLC (Not CME Accredited Session) (ID 967)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/26/2018, 12:00 - 13:30, Exhibit Hall
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P3.01-26 - A Framework for Systematic Clinical Evaluation of Technical Innovations in Lung Cancer Patients Treated on the MR-Linac (MRL) (ID 12562)
12:00 - 13:30 | Author(s): Jose Belderbos
- Abstract
Background
A recent innovation in radiotherapy is the MRL developed by Elekta and Philips. The MRL combines a 1.5 T MRI with a 7 MV linac. It allows the acquisition of high resolution MR images for on treatment verification, adaption and response monitoring.
a9ded1e5ce5d75814730bb4caaf49419 Method
Seven cancer institutions from Europe and North America, are working within the Elekta MR-Linac Consortium to evaluate the MRL within a framework called ‘R-IDEAL’ (Radiotherapy Idea Development Exploration Assessment Long-term Evaluation) 1.
4c3880bb027f159e801041b1021e88e8 Result
The table below summarizes the ongoing and planned work within the Elekta MR-Linac Consortium.
Progress to date:
8eea62084ca7e541d918e823422bd82e Conclusion
Stage 0: We defined in 80 patients the optimal MRI sequences suitable for GTV and organ at risk (OAR) contouring: T2 Turbo Spin Echo (TSE), T2 TSE with fat sat, T1 radial gradient echo, and DIXON TSE. Two radiology-led workshops were organized and inter-observer agreement was assessed for OARs. These led to a consensus-based OAR atlas. A study is being prepared to compare the image quality of the current standard CBCT and MR images at baseline and mid-treatment for treatment verification and set-up correction.
Stage 1: we will investigate the clinical feasibility of the MRL for standard of care radiotherapy and the scope for adaptive radiotherapy (margin reductions) and detecting changes in oxygenation during treatment on the MRL in patients with locally advanced (LA) NSCLC .
Stage 2a/b : Based on the results from stage 1 we will design a study aiming to reduce margins around the tumour and dose escalate in patients with LA NSCLC.
The aim of this programme of work is to generate robust evidence to support the introduction of the MRL and to improve outcomes of patients with LA NSCLC.
6f8b794f3246b0c1e1780bb4d4d5dc53
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P3.16 - Treatment of Early Stage/Localized Disease (Not CME Accredited Session) (ID 982)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/26/2018, 12:00 - 13:30, Exhibit Hall
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P3.16-17 - Cardiac Sparing in Stereotactic Body Radiotherapy of Early Stage NSCLC Patients (ID 13855)
12:00 - 13:30 | Presenting Author(s): Jose Belderbos
- Abstract
Background
In NSCLC patients who receive radiotherapy, cardiac toxicity was not well established as a possible factor until the results of the RTOG 0617 showed associations between cardiac dose and survival. These associations have been confirmed both in early and in locally advanced stage NSCLC patients. Cardiac sparing is not yet systematically pursued, and there is currently no agreement on cardiac constraints to be used. We investigated the feasibility of cardiac sparing in early stage NSCLC patients who receive SBRT.
a9ded1e5ce5d75814730bb4caaf49419 Method
Ten patients with early stage NSCLC in a middle or lower lobe, treated to 3x18 Gy between 2015 and 2017 using a dual arc VMAT technique were randomly selected. Retrospectively, clinical plans were adapted to minimize the maximum heart dose, while clinical constraints were respected. Mean Lung Dose (MLD) and cardiac doses Dmax, Dmean and V5Gy were compared between clinical and cardiac spared plans using a paired t-test.
4c3880bb027f159e801041b1021e88e8 Result
Median GTV was 3.05cc (range 0.54-23.2cc), 7 left sided tumors, 3 right sided. All cardiac spared plans fulfilled the clinical constraints on tumor coverage, conformity and organs at risk. All cardiac parameters were significantly decreased; a reduction in max heart dose of 8.2 Gy, reduction in mean heart dose of 1.0 Gy, and reduction in heart V5Gy of 10.3%, with p-values <0.001, 0.008 and 0.014 respectively. MLD was increased by a mean of 0.51 Gy (p-value 0.002). Results are shown in table 1.
8eea62084ca7e541d918e823422bd82e ConclusionDifference in cardiac and lung doses between clinical plans and cardiac spared plans. Patient Difference Heart_Dmax (Gy) Difference Heart_Dmean (Gy) Difference Heart_V5 (%) Difference MLD (Gy) 1
-6.1
-0.2
-2.5
0.2
2
-6.6
-0.9
-6.8
0.5
3
-2.8
0
-0.1
0.1
4
-8
-0.5
-3.7
0.8
5
-8
-0.2
-1.9
0.7
6
-8.6
-1.8
-13.4
0.2
7
-12.8
-2.9
-34.9
1.3
8
-12.4
-0.4
-5.6
0.2
9
-7.4
-1.4
-14.8
0.6
10
-9.4
-1.9
-19.5
1
Average
-8.21
-1.02
-10.32
0.56
Cardiac sparing is feasible for early stage NSCLC patients treated with SBRT, without compromising target coverage, and with minimal increase in mean lung dose. As cardiac exposure is associated with increased mortality, cardiac sparing has the potential to increase survival, and should be considered for all early stage NSCLC patients treated with radiotherapy. These data will need to be confirmed in a larger, prospective cohort.
6f8b794f3246b0c1e1780bb4d4d5dc53
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PL04 - Take Action - Key Messages from WCLC 2018 and Goals for 2019 (ID 852)
- Event: WCLC 2018
- Type: Plenary Session
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/26/2018, 15:15 - 16:30, Plenary Hall
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PL04.04 - Radiation Oncology (ID 11660)
15:45 - 15:55 | Presenting Author(s): Jose Belderbos
- Abstract
- Presentation
Abstract not provided
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