Spinal Instability Score Associated With Pain Response to Radiotherapy
Patients with a SINS of 6 or lower can be effectively treated with palliative spinal radiotherapy, but patients with a SINS 7 or greater will likely achieve only a partial response.
Complete pain response to spinal radiotherapy is associated with a Spinal Instability Neoplastic Score (SINS) of 7 or lower, according to a study published in The Oncologist.1
Retrospective data suggest that a higher SINS score is associated with radiotherapy failure. This study aimed to confirm this finding in a prospective setting.
SINS includes measurements of metastases location, pain, type of lesion, radiographic spinal alignment, vertebral body collapse, and the posterolateral involvement of spinal elements. The score range is 0 to 18 points, with higher scores indicating spinal instability.
This observational cohort study evaluated 124 patients with symptomatic spinal metastases undergoing palliative radiotherapy between 2013 and 2015.
Baseline characteristics were similar among the groups, except more patients who responded to radiotherapy had a World Health Organization performance score of 0 to 2 compared with non-responders (96% vs 81%, respectively; P = .017).
Spinal radiotherapy resulted in a complete response for 16 patients and a partial response for 65. Lower SINS was significantly associated with complete response (adjusted odds ratio [OR], 0.78; 95% CI, 0.62-0.98; P = .030).
SINS was not, however, associated with overall pain response (adjusted OR, 0.94; 95% CI, 0.81-1.10; P = .449). According to the authors, “this might indicate that this referral tool is not yet optimal for prediction of treatment outcome.”
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The results of this study suggest that patients with a SINS of 6 or lower can be effectively treated with palliative spinal radiotherapy, but patients with a SINS 7 or greater will likely achieve only a partial response and should be referred to a spine surgeon.
- van der Velden JM, Versteeg AL, Verkooijen HM, et al. Prospective evaluation of the relationship between mechanical stability and response to palliative radiotherapy for symptomatic spinal metastases. Oncologist. 2017 May 3. doi: 10.1634/theoncologist.2016-0356 [Epub ahead of print]