A revised scoring system for preoperative evaluation of metastatic spine tumor prognosis

Abstract

Study design: A semi-prospective clinical study was conducted.

Objectives: To evaluate the accuracy of a revised scoring system predicting metastatic spinal tumor prognosis and the suitability of the subsequent treatment strategy.

Summary of the background data: We used a scoring system for the preoperative evaluation of the prognosis of metastatic spinal tumors and selected treatment methods for the predicted prognosis. In the previous version of our scoring system, the reliability of the predicting prognosis was 63.3% in 128 patients with metastatic spinal tumors.

Methods: The study participants were 164 patients who died after surgery and 82 who died after conservative treatment. Six parameters were used in the revised scoring system. Each parameter ranged from 0 to 5 points, and the total score was 15 points. In principle, conservative treatment or palliative procedures were indicated in patients with a total score of 8 or less (predicted survival period, less than 6 months) or those with multiple vertebral metastases, while excisional procedures were performed in patients with a total score of 12 or more (predicted survival period, 1 year or more) or those with a total score of 9 to 11 (predicted survival period, 6 months or more) and with metastasis in a single vertebra. The selection of treatment modality was followed faithfully according to the criteria of the revised scoring system after 1998. The prognosis predicted by the revised scoring system and the actual survival period after treatment were compared, and the reliability of the prognostic criteria was analyzed for the group subjected to it prospectively after 1998 (n = 118) and for all 246 patients it was applied to retrospectively.

Results: The total score for each patient could be correlated with the survival period. This correlation was also observed in each treatment group. The consistency rate between the predicted prognosis from the criteria of the total scores and the actual survival period was high in patients within each score range (0-8, 9-11, or 12-15), 86.4% in the 118 patients evaluated prospectively after 1998, and 82.5% in the 246 patients evaluated retrospectively. Furthermore, a similar result was also observed in both the surgical procedure group and conservative treatment group. The rate of consistency between the predicted prognosis and the actual survival period in each local extension of the lesion was 75% or more in all types, excluding Type 6 in the surgical classification of Tomita et al.

Conclusion: The prognostic criteria using the total scores from our revised scoring system were useful for the pretreatment evaluation of metastatic spinal tumor prognosis irrespective of treatment modality or local extension of the lesion.