Clinical outcomes following advanced respiratory motion management (respiratory gating or dynamic tumor tracking) with stereotactic body radiation therapy for stage I non-small-cell lung cancer

Abstract

PurposeTo report the outcomes of stereotactic body radiation therapy (SBRT) for stage I non-small-cell lung cancer (NSCLC) according to respiratory motion management method.MethodsPatients with stage I NSCLC who received SBRT from 2007 to 2015 were reviewed. Computed tomography (CT) simulation with four-dimensional CT was performed for respiratory motion assessment. Tumor motion >1 cm in the craniocaudal direction was selectively treated with advanced respiratory management: either respiratory gating to a pre-specified portion of the respiratory cycle or dynamic tracking of an implanted fiducial marker. Comparisons were made with internal target volume approach, which treated all phases of respiratory motion.ResultsOf 297 patients treated with SBRT at our institution, 51 underwent advanced respiratory management (48 with respiratory gating and three with tumor tracking) and 246 underwent all-phase treatment. Groups were similarly balanced with regard to mean age (P=0.242), tumor size (P=0.315), and histology (P=0.715). Tumor location in the lower lung lobes, as compared to middle or upper lobes, was more common in those treated with advanced respiratory management (78.4%) compared to all-phase treatment (25.6%, P<.0001). There were 17 local recurrences in the treated lesions. Kaplan–Meier analyses showed that there were no differences with regard to mean time to local failure (91.5 vs 98.8 months, P=0.56), mean time to any failure (73.2 vs 78.7 months, P=0.73), or median overall survival (43.3 vs 45.5 months, P=0.56) between patients who underwent advanced respiratory motion management and all-phase treatment.ConclusionSBRT with advanced respiratory management (the majority with respiratory gating) showed similar efficacy to all-phase treatment approach for stage I NSCLC.

Photonic Reservoir Computing for Real-Time Respiratory Motion Prediction

“…RC for improved radiation delivery efficiency. In a clinical setting, the real-time photonic TDR respiratory motion prediction strategy and instrumentation described here is anticipated to be adopted in a dynamic tracking system used in combination with the respiratory gating for radiotherapy 31,32,33 . Radiation is synchronized with the gating window and the beam is only de-shuttered when the position prediction error is lower than a pre-set error margin.…”

“…For a majority of the 76 motion curves used in this study, a therapeutic beam exposure efficiency of 80% can be obtained for AE < 1 mm for all three look-ahead times while > 98% efficiency for AE < 3 mm margin. In comparison, the current clinically implemented respiration gating method is typical to set the gating phase of 20% to 70% 33 . Assuming equal time in each phase, the radiation beam is on for phases from 0% to 20% and 70% to 90%, giving ~ 50% as the radiotherapy beam exposure time efficiency.…”

<p>Outcomes Following Stereotactic Body Radiotherapy with Intensity-Modulated Therapy versus Three-Dimensional Conformal Radiotherapy in Early Stage Non-Small Cell Lung Cancer</p>

“…Patients were treated either with an internal target volume (ITV) approach, where the entirety of motion was encompassed in planning target volume, or advanced respiratory motion management techniques (Phase-based respiratory gating, dynamic tumor tracking). Effect of respiratory management method was previously reported to have no appreciable influence on clinical outcomes 14. Patients were treated on one of four treatment machines: Varian 21EX, Varian TrueBeam, Accuray Tomotherapy, and Brainlab Vero.…”

Potential Morbidity Reduction for Lung Stereotactic Body Radiation Therapy Using Respiratory Gating

“…In another method called respiratory gating, the treatment beam is switched off when the tumor moves out of a predefined motion window. Several studies revealed a comparable efficacy of the gating concept to other motion mitigation methods [24,25].…”