Oral Presentation 50th International Society for the Study of the Lumbar Spine Annual Meeting 2024

Introduction. In advanced-age patients, frailty—aging-related decrease in physiological reserves and increase in vulnerability to physiological stressors—dictates surgical outcomes and survival in patients with cancer.¹ Although we identified the modified Frailty Index (mFI)-11≥0.23 as the risk factor for postoperative complications in patients with spinal metastases,² the impact of frailty on survival is still unclear. This study aims to elucidate the effects of frailty on survival after spinal metastases surgery.

Methods. We prospectively analyzed 158 patients aged 65 years or older with spinal metastases who underwent palliative surgery at our institution from 2015 to 2021 due to progressive neurological deficits or intractable pain. The postoperative survival duration was defined as the time from the date of surgery to the latest follow-up examination or death. Age, sex, lesion location, Spinal Instability Neoplastic score (SINS), new Katagiri score (including primary site, visceral metastasis, laboratory data, performance status (PS), and chemotherapy), preoperative radiotherapy, and mFI-11 were recorded at surgery and considered to be possible predictors based on prior reports.^3,4 The overall survival rate was calculated by the Kaplan-Meier method and compared by the log-rank method between patients with mFI≥0.23 and <0.23. The mean mFI between patients who were alive and dead at 3 and 6 months after surgery was compared using unpaired t-test. Possible prognostic factors with a P value <0.05 in the univariate Cox regression analysis were entered into the multivariate Cox regression analysis.

Results. Posterior decompression and instrumentation (n=122) or posterior instrumentation alone (n=36) was performed at a mean age of 73.7±6.1 years. The median survival time was 4.4 (95% confidence interval [CI], 3.2–5.6) months in patients with mFI≥0.23, while 27.9 (95%CI, 0.0–57.8) months in those with mFI<0.23 (p=0.008) (Fig. 1). Additionally, the mean mFI in patients who died within 3, and 6 months (0.17±0.08,0.16±0.07) were significantly lower than that in patients who were alive at 3 and 6months (0.23±0.11, 0.22±0.10) after surgery (p=0.003, 0.004). In the univariate analysis, male sex (Hazard ratio [HR], 1.64; p=0.046); moderate growth (HR, 3.66; p=0.001) and rapid growth (HR, 10.44; p<0.001) at the primary site; nodular metastasis (HR, 2.12; p=0.003) and disseminated metastasis (HR, 2.87; p=0.009); abnormal laboratory data (HR, 2.71; p=0.001); PS≥3 (HR, 2.66; p=0.001); previous chemotherapy (HR, 1.84; p=0.009); and mFI≥0.23 (HR, 1.90; p=0.009) were associated with poor survival (Table 1). In the multivariate analysis, moderate growth (HR, 3.37; 95%CI, 1.53–7.43; p=0.003) and rapid growth (HR, 9.71; 95%CI, 4.36–21.61; p<0.001) at the primary site; disseminated metastasis (HR, 3.80; 95%CI, 1.31–6.30; p=0.002); PS≥3 (HR, 2.54; 95%CI, 1.37–4.71; p=0.003); previous chemotherapy (HR, 1.89; 95%CI, 1.17–3.07; p=0.010); and mFI≥0.23 (HR, 1.76;95%CI, 1.03–3.01; p=0.040) were significantly associated with poor survival (Table 2).

DISCUSSION.

As prediction of life expectancy in patients with spinal metastases is the most important step in determining the optimal treatment, many prognostic scoring systems have been developed. However, frailty have not been taken into account. The current study demonstrated that mFI≥0.23 with prognostic scoring system should be contributed to more accurate prognosis in patients with spinal metastases.