Poster Presentation 51st International Society for the Study of the Lumbar Spine Annual Meeting 2025

Modified frailty index enhanced the discrimination ability of the existing prognostic scoring system in elderly patients with spinal metastases (#153)

Yutaro Kanda 1 , Tomoya Matsuo 1 , Takashi Yurube 1 , Takeru Tsujimoto 1 , Yoshiki Takeoka 1 , Kunihiko Miyazaki 1 , Masao Ryu 1 , Naotoshi Kumagai 1 , Kohei Kuroshima 1 , Yoshiaki Hiranaka 1 , Masahiko Furuya 1 , Daisuke Nakagawa 1 , Yu Inoue 1 , Ryosuke Kuroda 1 , Kenichiro Kakutani 1
  1. Kobe University Graduate School of Medicine, Kobe, Japan

Introduction. We have identified the modified Frailty Index (mFI)-11≥0.27 as the risk factor for postoperative complications in patients with spinal metastases.1 However, the impact of frailty on survival is still unclear. This study aims to elucidate the effects of frailty on survival and to validate the effectiveness of the existing scoring system with mFI for survival estimation 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. Age, sex, lesion location, Spinal Instability Neoplastic score (SINS), new Katagiri score (including primary site, visceral metastasis, laboratory data, performance status (PS), bone metastasis, and chemotherapy), preoperative radiotherapy, and mFI-11 were recorded at surgery and considered to be possible predictors based on prior reports.2,3 Possible prognostic factors with a P value <0.05 in the univariate Cox regression analysis were entered into the multivariate Cox regression analysis. The discrimination ability of the new Katagiri score with mFI for predicting survival was evaluated using Harrell’s C-index.

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). The number of items of mFI negatively correlated with survival. 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. 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. By including mFI≥0.27 in the New Katagiri score, the discrimination ability improved from 0.813 to 0.832 at 6 months and from 0.747 to 0.818 at 1 year, while the discrimination ability did not change at 3 months.

DISCUSSION.

As the prediction of life expectancy in patients with spinal metastases is essential for determining the optimal treatment, many prognostic scoring systems have been developed. However, frailty has not been taken into account. The current study demonstrated that mFI≥0.27 should contribute to more accurate survival estimation in patients with spinal metastases.

  1. 1. Matsuo T. Bone Joint J In press. 2. Bollen L. Eur Spine J. 2018. 3. Miyaji Y. Cancer Diagn Progn. 2023.