Commentary on “Baseline Frailty Measured by the Risk Analysis Index and 30-Day Mortality After Surgery for Spinal Malignancy: Analysis of a Prospective Registry (2011–2020)”
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In the past decades, thanks to medical advances, the survival of cancer patients has improved, and the incidence of the spine metastasis has also increased. Numerus studies have focused on predicting the survival of spine metastasis patients, leading to the development of several prediction systems such as Tomita score, revised Tokuhashi score, modified Bauer score, New England Spine Metastasis Scores, SORG nomogram… etc [1]. While surgery for spine metastasis primarily aims for the mechanical stabilization and neurological restoration, the patient’s postoperative survival is a crucial factor that should be considered preoperatively.
In addition to survival, frailty has garnered increasing interests [2]. Frailty is a recognized geriatric syndrome that predicts poor outcomes and is characterized by and age-related and precipitous decline in function. It also indicates a reduced ability to recover from physiological stresses. For instance, in a surgical cohort of spine metastasis from non-small cell lung cancer, aggressive surgery showed longer overall survival and progression-free survival to ambulatory patients compared to palliation surgery, but it also demonstrated higher mortality rates at the 30 and 90 days [3]. Assessing frailty is therefore critical in the decisionmaking process for surgery [4]. The Modified Frailty Index (mFI), a cumulative and weighted deficit model developed by Rockwood et al. [5], is considered an appropriate risk stratification tool in spine surgery [4]. However, in the context of the spine metastasis surgery, the mFI does not account for the impact of systemic treatment—chemotherapy, disease burden, and performance status—ECOG, which are important factors in determined how well a patient can tolerate the surgery [2].
Nutritional status is also related to survival and complications following spine metastasis surgery [6]. Besides survival prediction and frailty evaluation, nutrition plays an important role in the postoperative course and should be considered in treatment plan, though it is not a part of 5-factor mFI (mFI-5) or 11-factor mFI evaluations. Consequently, new tools are being developed. The Metastatic Spinal Tumor Frailty Index, which includes nine independent variables such as malnutrition and surgical invasiveness [7], has been frequently studied but lack predictive validity. The Hospital Frailty Risk Score has shown positive predictive validity, but it is not clinical feasible as it is measured based on administrative data [8]. The H2-FAILS score, which includes serum albumin level for nutrition evaluation and performance status, demonstrated better prediction of 30-day mortality then the mFI-5 [9]. The Risk Analysis Index (RAI) for spinal malignancy surgical outcomes has shown superiority in prediction of mortality/hospice rates versus mFI-5 and chronological age [10]. Compared to other frailty tools, RAI involves more performance and nutritional evaluations, such as exertional tachypnea, dependency of daily living, weight loss, and appetite [11].
There is no perfect prediction system for survival evaluation of spine metastasis patients, nor is there a perfect tool for frailty. Most tools are not proven accurate enough for clinical utility [12], and no frailty tools have been investigated for reliability. Frailty is only a part of preoperative evaluation and should not be the sole factor in deciding whether to proceed with surgery. The extent of surgical intervention and invasiveness should be balanced with the frailty status. An international retrospective cohort study showed that the spine metastasis patients have equal satisfaction with surgery wheter they survive less and more than three months [13].
Survival prediction is challenging and continually evolving. Frailty represents the physiologic resilience of a patient to tolerate surgery. In conclusion, for spine metastasis patients, frailty encompasses comorbidities, performance status, nutrition, disease burden, and the impact of systemic treatment. There is no perfect frailty tool yet and frailty alone should not be used to refuse surgery for spine metastasis patients. Patient preference and satisfaction also matter. Further studies are needed to clarify how frailty should be evaluated, to validate these evaluations, and to determine whether nutrition supplementation and prehabilitation are effective interventions to reverse frailty.
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Conflict of Interest
The author has nothing to disclose.