Spinal stereotactic body radiotherapy in the United States: A decade-long nationwide analysis of patient demographics, practice patterns, and trends over time

Nationwide utilization of spinal stereotactic body radiotherapy (SBRT) is not known; to address this void, the National Cancer Data Base (NCDB) from 2004 to 2013 was used for analysis. Spinal SBRT was defined as 1–5 fractions (14–32 Gy) delivered to the cervical, thoracic, lumbar or sacral spine. From 2004 to 2013, 1044 patients received spinal SBRT, most commonly in single-fraction (38%), three-fraction (26%) and five-fractions (25%). Metastatic spinal disease most commonly originated from the lung (34%), kidney (14%), and blood (9%). The most common insurance status receiving spinal SBRT was private (44%) followed by Medicare (43%), with Medicaid (8%) a distant third. Fifty-six percent of patients were male, and 55% of patients were younger than age 65. 80% of patients were Caucasian, with 13% being African-American. The vast majority (74%) of patients had no Charlson/Deyo comorbidities. The incidence of spinal SBRT gradually increased over time, rising from 2% to 20% of cases from 2004 to 2013. Comprising only 1.4% of spinal metastases radiation in 2004, SBRT rose to a 5.8% share in 2013. In conclusion, SBRT for spine metastases in the United States has more than quadrupled in utilization over a recent ten-year span. Although the majority of spinal SBRT is multi-fraction, the most popular fractionation scheme was single-fraction. It has been most commonly used for Caucasian men under age 65 with private/Medicare insurance and no comorbidities. By far the most common origin of spinal metastases treated by SBRT was the lung, followed by renal cancer. These results provide a baseline for further prospective investigation.