Page 46 - Predicting survival in patients with spinal bone metastasesL

CHAPTER III
Pointillart et al.17 found the KPS to be a significant predictor of survival on univariate analysis, but unfortunately did not perform an analysis for each category. In their study the HR was equal to 0.98 (p=0.002, 95%CI 0.96-0.99), indicating that performance status was not clinically relevant.
In a retrospective study, evaluation of performance status is challenging, especially when trying to avoid the influence of neurologic deficit. The data does suggest an effect of performance status on survival, but only on multivariate analysis and when divided in three groups. The HR for a KPS score 50-70 is equal to 1.3, (p=0.292, 95%CI 0.8-2.1), but the HR for a KPS score 10-40 is equal to 2.7 (p=0.025, 95%CI 1.1-6.6).
Chi et al.18 considered the effects of age in predicting survival as well as preservation of ambulation for patients treated for spinal metastases. We agree that particular age cutoff points can help in selecting patients, but did not find their suggested age of 65 to be accurate in this population (p=0.089).
Neurologic deficit has no significant effect on survival (p=0.196), stressing that this variable should be excluded when evaluating performance status. Even though survival is not affected by neurologic functioning, it is an important factor that should be considered when deciding on treatment.
In patients with malignancies, the presence of bone metastases can be used as a marker for progression of disease. However, if a patient is already affected by spinal bone metastases, the presence or absence of extraspinal bone metastases is inconsequential. Neither the classification according to Tokuhashi (p=0.970), nor the classification according to Tomita or Bauer (p=0.946) resulted in a significant effect. The amount (p=0.860) and location (p=0.493) of spinal metastases have no impact on survival. Similar to neurologic functioning it does however have consequences when deciding on treatment. Feasibility, approach and extent of surgery should be weighed against amount of metastatic involvement of the spinal column and location of the symptomatic metastases.
Based on these results it can be argued that there are several flaws in the current scoring systems. Firstly, the primary tumor classifications need to be updated based on larger populations. Our experience is that the Tomita classification is the ideal
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