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Updated: Jul 12, 2026
Stereotactic Radiosurgery for Gynecologic Cancer
Published on: April 17, 2012
Multi-institutional Analysis of MR-Guided Single-Fraction Stereotactic Ablative Body Radiation Therapy: Feasibility,
Frederik Fuchs1, Roberto Herrera2, Rupesh Kotecha2
1Department of Radiation Oncology, University Hospital, LMU Munich, Munich, Germany.
Purpose:
Stereotactic ablative body radiation therapy (SABR) is commonly delivered in multiple fractions, whereas single-fraction (SF) SABR remains uncommon. Magnetic resonance (MR)-guided linacs provide superior soft-tissue contrast compared to cone-beam computed tomography on conventional linacs, online adaptive replanning, continuous intrafraction visualization, and automatically triggered beam delivery, potentially enabling safe and effective SF-SABR.
Methods And Materials:
We retrospectively analyzed patients treated with MR-guided SF-SABR on a 0.35 Tesla MR-linacs (ViewRay Inc, MRIdian) at 2 centers in Germany and the United States. Median SF-SABR doses were 28 Gy (range, 28-40 Gy) for liver lesions, 30 Gy (range, 28-34 Gy) for lung lesions, 25 Gy for adrenal gland lesions and lymph nodes, and 26 Gy (range, 25-26 Gy) for renal lesions. Endpoints included local control (LC), progression-free survival, overall survival (OS), and toxicity graded according to Common Terminology Criteria for Adverse Events version 5.0.
Results:
Between April 2020 and December 2024, 161 patients with 175 lesions underwent MR-guided SF-SABR. Lesion distribution was liver (48.0%), lung (42.9%), adrenal gland (4.3%), lymph nodes (3.4%), and kidney (1.9%). Median gross tumor volume and planning target volume were 2.4 cc (range, 0.2-83.3 cc) and 9.3 cc (range, 1.4-112.1 cc), respectively. At a median follow-up of 19.3 months, LC rates at 1 and 2 years were 99.1% and 93.6%, respectively. Progression-free survival rates at 1 and 2 years were 59.3% and 51.4%, while OS rates were 81.8% and 73.4%, respectively. Treatment was well tolerated, with only one acute grade 3 toxicity reported and no acute grade 4-5 or late grade 3-5 toxicities. Colorectal primary tumors were associated with poorer LC (hazard ratio [HR] = 0.226; P = .023). Larger gross tumor volume independently correlated with reduced LC (HR = 1.15; P = .048) and OS (HR = 1.05; P = .001).
Conclusions:
MR-guided SF-SABR is feasible, safe, and effective across various tumor locations, providing favorable LC with minimal toxicity, warranting further prospective evaluation.
