Local control and vertebral compression fractures following stereotactic body radiotherapy for spine metastases

Yurday Ozdemir; Nese Torun; Ozan Cem Guler; Berna Akkus Yildirim; Ali A Besen; Aylin Gunesli Yetisken; H Cem Onal; Erkan Topkan

doi:10.1016/j.jbo.2019.100218

Local control and vertebral compression fractures following stereotactic body radiotherapy for spine metastases

J Bone Oncol. 2019 Jan 24:15:100218. doi: 10.1016/j.jbo.2019.100218. eCollection 2019 Apr.

Authors

Yurday Ozdemir¹, Nese Torun², Ozan Cem Guler¹, Berna Akkus Yildirim¹, Ali A Besen³, Aylin Gunesli Yetisken⁴, H Cem Onal¹, Erkan Topkan¹

Affiliations

¹ Department of Radiation Oncology, Baskent University Medical Faculty, Kisla Saglik Yerleskesi, 01120 Adana, Turkey.
² Department of Nuclear Medicine, Baskent University Medical Faculty, Adana, Turkey.
³ Department of Medical Oncology, Baskent University Medical Faculty, Adana, Turkey.
⁴ Department of Radiology, Baskent University Medical Faculty, Adana, Turkey.

Abstract

Purpose: We aimed to retrospectively assess the incidence of vertebral compression fractures (VCF), examine clinicopathologic factors potentially associated with VCF, and evaluate treatment response in patients who received stereotactic body radiotherapy (SBRT) for spine metastases (spMets).

Methods and materials: We identified 78 patients with 125 spMets at baseline and subsequent assessments. Patients received SBRT doses of 16 or 18 Gy. Patients with pre-existing VCF and co-existing local progression were excluded. Spine instability neoplastic score (SINS) was used for spMets categorization. Response to SBRT and VCF were assessed according to the Positron Emission tomography Response Criteria In Solid Tumors (PERCIST) and Genant scores, respectively. Kaplan-Meier analyses were used to assess local control of disease and vertebral compression fracture-free survival (FFS).

Results: We treated 103 cases with single spMets and 11 cases involving double spMets with SBRT. Progressive disease was reported in 3.2% and 8.2% of the cases in the first and last PET/CT reports, respectively. The distribution of treatment response in the remaining patients was: complete response in 30.6% of patients, partial response in 47.1% of patients, and stable disease in 22.3% of patients in the first PET/CT; complete response in 62.3% of patients, partial response in 16.7% of patients, and stable disease in 21% of patients at the last monitoring. Local failures were observed in 15 (12%) of cases. Median SINS was 5 (range: 1-13); majority of patients in our cohort (70.4%) were categorized as stable according to SINS, five (4%) patients had Grade 3 VCF at a median time of 16 months after SBRT (range: 2-22 months), and 60% of VCF occurred after an interval of at least 12 months after SBRT. No bisphosphonate usage was significantly associated with VCF (r = -0.204; p = 0.022). Median FFS was 21 months. Univariate analyses indicated that female gender (p < 0.001), bisphosphonate use (p = 0.005), >6 months of bisphosphonates use (p = 0.002), and the lowest vertebral body collapse score (p = 0.023) were associated with higher FFS. Female gender (p = 0.007), >6 months of bisphosphonates usage (p = 0.018), and the lowest vertebral body collapse score (p = 0.044) retained independent significance.

Conclusions: This study demonstrated that spine SBRT with doses of 16-18 Gy promises good local control of disease with acceptable VCF rates. Lowest vertebral body collapse score, female gender, and >6 months of bisphosphonate use were significantly associated with longer FFS.

Keywords: Bisphosphonate; FFS, vertebral compression fracture-free survival; PERCIST, Positron Emission tomography Response Criteria in Solid Tumors; PET/CT; PSMA, prostate-specific membrane antigen; SBRT; SBRT, stereotactic body radiotherapy; SINS, spine instability neoplastic score; SUL, lean body mass SUV; SUV, standardized uptake values; Spine metastases; VCF, vertebral compression fractures; Vertebral compression fracture; spMets, spine metastases.