Purpose: Palliative radiotherapy is routinely used to treat painful spinal metastases from renal cell carcinoma (RCC). Conventionally planned external beam radiotherapy (CRT) has been standard, with high-dose stereotactic body radiotherapy (SBRT) becoming increasingly common given the radioresistant nature of RCC. We compared the efficacy and durability of pain relief produced by these 2 modalities.
Methods and materials: Patients with painful spinal metastases from RCC treated from 2002-2010 were included. Response was defined similar to the Radiation Therapy Oncology Group 0631 protocol: complete response (CR) being resolution of pain without increased narcotics; partial response (PR) included patients with an incomplete reduction in pain without increased narcotics. Patients who experienced a CR or PR were coded as having pain relief, while those with persistent pain or additional narcotics requirements were coded as failures. Achievement of pain relief was analyzed using competing risk analysis with death as the competing event. Time to pain relief was plotted using cumulative incidence analysis.
Results: A total of 110 patients (34 CRT; 76 SBRT) were included. Median follow-up was 4.3 months (range, 0.2-38). Median Karnofsky performance score was higher for patients treated with SBRT compared with CRT (80 vs 70; P = .0004). Overall pain response rates were 68% for CRT and 62% for SBRT, with respective CR and PR rates of 12% and 56% for CRT, and 33% and 29% for SBRT (P = .01). Median time to pain relief was 0.6 weeks for CRT versus 1.2 weeks for SBRT (P = .29). For patients who achieved pain relief (n = 79), median duration was 1.7 months for CRT versus 4.8 months for SBRT (P = .095). On univariate analysis no factors were significantly related to pain relief.
Conclusions: CRT was not statistically different than SBRT for pain relief in symptomatic spine metastases from RCC and should be used as first line treatment. The appropriate use of SBRT in this population merits prospective study.
Copyright © 2012 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.