The Clinical Frailty Scale as useful tool in patients with brain metastases.

Purpose: The Clinical Frailty Scale (CFS) evaluates patients' level of frailty on a scale from 1 to 9 and is commonly used in geriatric medicine, intensive care and orthopedics. The aim of our study was to reveal whether the CFS allows a reliable prediction of overall survival (OS) in patients after surgical treatment of brain metastases (BM) compared to the Karnofsky Performance Score (KPS).

Methods: Patients operated for BM were included. CFS and KPS were retrospectively assessed pre- and postoperatively and at follow-up 3-6 months after resection.

Results: 205 patients with a follow-up of 22.8 months (95% CI 18.4-27.1) were evaluated. CFS showed a median of 3 ("managing well"; IqR 2-4) at all 3 assessment-points. Median KPS was 80 preoperatively (IqR 80-90) and 90 postoperatively (IqR 80-100) as well as at follow-up after 3-6 months. CFS correlated with KPS both preoperatively (r = - 0.92; p < 0.001), postoperatively (r = - 0.85; p < 0.001) and at follow-up (r = - 0.93; p < 0.001). The CFS predicted the expected reduction of OS more reliably than the KPS at all 3 assessments. A one-point increase (worsening) of the preoperative CFS translated into a 30% additional hazard to decease (HR 1.30, 95% CI 1.15-1.46; p < 0.001). A one-point increase in postoperative and at follow-up CFS represents a 39% (HR 1.39, 95% CI 1.25-1.54; p < 0.001) and of 42% risk (HR 1.42, 95% CI 1.27-1.59; p < 0.001).

Conclusion: The CFS is a feasible, simple and reliable scoring system in patients undergoing resection of brain metastasis. The CFS 3-6 months after surgery specifies the expected OS more accurately than the KPS.