Radiosurgery for Treatment of Renal Cell Metastases to Spine: A Systematic Review of the Literature.

BACKGROUND

The incidence of renal cell carcinoma (RCC) continues to increase, and the spine is the most common site for bony metastasis. Radiation therapy is one treatment for spinal RCC metastasis. Stereotactic body radiotherapy (SBRT) is a newer treatment that reportedly has benefits over conventional external beam radiotherapy. This study systematically reviewed the current literature on SBRT for metastatic RCC to spine.

METHODS

A search of PubMed, Embase, and Scopus databases was conducted in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Clinical articles evaluating SBRT for RCC metastases were identified. After inclusion and exclusion criteria were applied, the search resulted in 9 articles. Data including pain outcomes, local control, survival outcomes, vertebral compression fracture (VCF), and toxicity were extracted and evaluated.

RESULTS

The studies analyzed showed an improvement in pain in 41%-95% of patients. Local control rates after SBRT ranged 71.2%-85.7% at 1 year, a significant improvement when compared with conventional external beam radiotherapy. The rate of VCF after treatment with SBRT ranged 16%-27.5%, with single-fraction therapy being a risk factor for increased incidence. Overall toxicity rates ranged 23%-38.5%, with only 3 cases of grade 3 toxicity (nausea) and no cases of radiation myelitis.

CONCLUSIONS

Use of SBRT for spinal metastasis from RCC resulted in significant local control and pain outcomes. There is a risk of VCF with SBRT; however, treatment seems to be well tolerated with few serious side effects. There is continued need for long-term prospective studies investigating the optimal role of SBRT in the treatment algorithm of RCC spinal metastases.