Main Session
Sep
27
PQA 01 - Gastrointestinal Cancer and Central Nervous System
2160 - BLAZE (Boosted Lesion Ablative Zone Escalation) in Spinal Radiation Therapy: A Systematic Review and Meta-Analysis of Safety and Efficacy
Presenter(s)
Alexis Narvaez Rojas, MD - Maimonides Medical Center, New York, NY
A. R. Narvaez Rojas1,2, G. S. Quirequire3, J. P. Rowley1, D. L. Schwartz4, and J. Wallach4,5; 1Maimonides Medical Center, Brooklyn, NY, 2Hospital Militar Escuela Alejandro Davila Bolanos, Managua, Nicaragua, 3Woodhull Medical Center, Brooklyn, NY, 4Veterans Affairs New York Harbor Healthcare System, Brooklyn, NY, 5SUNY Downstate Medical Center, Brooklyn, NY
Purpose/Objective(s):
Radiotherapy dose escalation for metastatic spinal disease is limited by potentially serious treatment side effects. The simultaneous integrated boost (SIB) technique enables intensification to gross tumor while delivering lower doses to adjacent volumes, with the intent of maximizing the therapeutic window. We performed a systematic review and proportion meta-analysis evaluating tumor control and safety of SIB-based dose escalation for metastatic vertebral lesions.Materials/Methods:
A PRISMA-guided systematic literature review was conducted to identify all studies reporting outcomes after SIB-based radiation for metastatic spinal lesions. Eligible series included stereotactic body radiotherapy (SBRT) and stereotactic-intent hypofractionated regimens incorporating SIB. Primary endpoints included 1-year local control (LC), 2-year LC, and the incidence of critical toxicities, specifically vertebral compression fracture (VCF) and radiation myelopathy (RM). A DerSimonian-Laird random-effects model was utilized to calculate pooled incidence proportion estimates with 95% confidence intervals (CIs). Inter-study heterogeneity was evaluated using the I2 statistic and Cochran’s Q test.Results:
A total of 12 studies comprising 1,353 spinal lesions were included. The pooled 1-year LC rate was 93.05% (95% CI: 90.18% - 95.13%; I2 = 51.2%, p = 0.020). With extended follow-up across 10 reporting studies (1,213 lesions), the pooled 2-year LC was 90.87% (95% CI: 86.75% - 93.80%; I2 = 68.5%, p < 0.001). The pooled incidence of VCF across all 1,353 lesions was 4.87% (95% CI: 3.55% - 6.65%), with low heterogeneity (I2 = 15.1%). Severe neurologic toxicity was exceedingly rare; across studies evaluating 1,135 patients, the pooled incidence of RM was 0.75% (95% CI: 0.34% - 1.66%; I2 = 0.0%). Where explicitly structured data was reported, complete pain resolution was achieved in a high proportion of patients (pooled estimate 47.1%), and the weighted average of reported median overall survival was 32.3 months. Leave-one-out sensitivity analysis confirmed the robust consistency of our pooled estimates, with 1-year LC remaining highly stable between 92.1% - 93.7% regardless of study omission. While Egger’s test indicated potential small-study publication bias (p < 0.001) typical of early institutional cohorts, random-effects modeling ensured appropriate conservative estimates.Conclusion:
Dose escalation with a SIB technique demonstrates durable 1- and 2-year LC rates exceeding 90%, with a VCF rate ~5% and a very low rate of RM. These encouraging pooled data support phase III prospective study of spinal SIB in metastatic spinal disease.