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

INTRODUCTION: The treatment techniques used for stereotactic body radiation therapy (SBRT) for early-stage lung cancer continue to evolve. In this study, clinical outcomes following SBRT were evaluated according to the use of either 3D conformal radiotherapy (3DCRT) or intensity-modulated radiation therapy (IMRT). PATIENTS AND METHODS: Patients with stage I NSCLC who received SBRT from 2007 to 2015 were retrospectively reviewed. Disease control and survival were assessed using Kaplan-Meier estimates. Dosimetric analyses for target dose heterogeneity and coverage were performed. RESULTS: A total of 297 patients with 351 lesions were included. 3DCRT was used in 52% and IMRT in 48%. IMRT was utilized at a higher rate in more recent years. The most common regimens were 48 Gy in 4 fractions and 54-60 Gy in 3 fractions. With a median follow up of 22.7 months, there were 17 local failures for a crude relapse rate of 5.7%. Local failure did not differ in patients treated with 3DCRT and IMRT (4.9% vs 6.5%, p=0.573). Mean dose to gross tumor volume (GTV) as a percent of prescription dose was higher with 3DCRT compared with IMRT (107.7% vs 103.6%, p < 0.0001). Tumor stage, histology, and SBRT regimen did not correlate with local tumor control. Overall survival for the entire population approximated 72% at 2 years. Treatment was well tolerated with 6 documented grade 3+ events. CONCLUSION: In this single-institution cohort of SBRT for early-stage NSCLC, there was no discernible difference in clinical outcomes between those treated with 3DCRT and IMRT.

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.

PURPOSE: To report the outcomes of stereotactic body radiation therapy (SBRT) for stage I non-small-cell lung cancer (NSCLC) according to respiratory motion management method. METHODS: Patients 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. RESULTS: Of 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. CONCLUSION: SBRT with advanced respiratory management (the majority with respiratory gating) showed similar efficacy to all-phase treatment approach for stage I NSCLC.