Pooled Analysis of Vertebral Endplate Disruption and Its Impact on Vertebral Compression Fracture Risk

Summary: Vertebral compression fracture (VCF) is a notable complication following spinal stereotactic body radiotherapy (SBRT). Previous studies have identified advanced Spinal Instability Neoplastic Score (SINS), endplate (EP) disruption, and adverse pathology as significant factors contributing to an increased risk of VCF. This study aims to expand the patient cohort to further explore the role of EP disruption in VCF development. This single-institution retrospective cohort study analyzed demographic and treatment data from patients who underwent spinal SBRT between 2013 and 2020. EP disruption was assessed using pre-SBRT CT scans. Chronic steroid use was defined as steroid administration for a duration of four weeks or longer. The 1-year cumulative incidence of VCF, was monitored through follow-up MRI and CT scans conducted at 3-month intervals post-treatment. 168 patients were included in the analysis, with a median follow-up of 18.7 months. Most patients (87%) underwent multi-fraction radiation therapy with a median dose of 27 Gy and a biologically effective dose (BED10) of 51.3 Gy. VCF occurred in 18% of patients, with a median onset of 4.8 months. The SINS score indicated that 55% of patients had a score below 7, 31% had a score of 7, and 14% had a score above 7. The 1-year cumulative VCF incidence revealed several key findings: primary cancers from non-small cell lung cancer (NSCLC), breast, and ano-colorectal origins exhibited a higher VCF rate (27%) compared to other types (12%) (p< 0.001). Chronic steroid use was significantly associated with increased VCF incidence (38% vs. 13%, p=0.01). Patients with a SINS score above 7 experienced a higher VCF rate (32%) than those with a score below 7 (4%) (p< 0.001). Bilsky grade 1 lesions had a higher VCF rate (28%) compared to grade 0 lesions (11%) (p=0.001). Additionally, EP disruption was significantly associated with VCF risk (31% vs. 5%, p< 0.001). Univariate analysis revealed that chronic steroid use, higher SINS score, Bilsky grade 1, EP disruption, adverse pathology, and circumferential treatment were associated with increased VCF risk, with hazard ratios (HR) for steroid use (HR 2.87, p=0.02), SINS score (HR 1.62, p< 0.001), Bilsky grade 1 (HR 3.19, p=0.002), EP disruption (HR 6.02, p< 0.001), adverse pathology (HR 3.31, p=0.001), and circumferential treatment (HR 2.26, p=0.03). Multivariable analysis confirmed that chronic steroid use (HR 2.91, p=0.04), SINS score (HR 1.31, p=0.005), EP disruption (HR 3.42, p=0.016), and adverse pathology (HR 2.81, p=0.007) were independent predictors of VCF risk. This expanded analysis reaffirms the association of EP disruption, adverse pathology, and higher SINS scores with an increased risk of VCF. Additionally, chronic steroid use for four weeks or longer was identified as a significant predictor of VCF risk. Khaled Dibs (he/him/his), MD (Presenting Author) - The Ohio State University; Emile Gogineni (he/him/his), DO (Co-Author) - The Ohio State University; Joshua D.. Palmer, MD (Co-Author) - Department of Radiation Oncology, The James Cancer Hospital and Solove Research Institute at The Ohio State University Wexner Medical Center; Evan Thomas (he/him/his), MD, PhD (Co-Author) - The Ohio State University; Raju Raval (he/him/his), MD, DPhil (Co-Author) - The Ohio State University; Sasha Beyer (she/her/hers), MD, PhD (Co-Author) - The Ohio State University; Vikram Chakravarthy, MD (Co-Author) - The Ohio State University; Brad Elder (he/him/his), MD (Co-Author) - The Ohio State University; Eric Bourekas, MD (Co-Author) - The Ohio State University; Daniel Boulter (he/him/his), MD (Co-Author) - The Ohio State University; Ahmed Elguindy (he/him/his), MD (Co-Author) - The Ohio State University; Eugene Yap (he/him/his), MD (Co-Author) - The Ohio State University; Russell Lonser (he/him/his), MD (Co-Author) - The Ohio State University; William S. Marras, PhD (Co-Author) - College of engineering; Mageswaran Prasath, PhD (Co-Author) - College of engineering; Arnab Chakravarti (he/him/his), MD (Co-Author) - The Ohio State University; Dukagjin Blakaj (he/him/his), MD, PhD (Co-Author) - The Ohio State University