A novel lesion severity index to predict 90-day postoperative survival in brain metastasis patients.

INTRODUCTION

Brain metastasis patients require granular surgical risk evaluation. The authors aimed to improve prognostication for brain metastasis patients by creating the Metastatic Brain Lesion Score (MBLS).

METHODS

This is a retrospective cohort study of patients undergoing craniotomy for brain metastasis between Jan 1, 2014 and Sept 30, 2021 at a large tertiary referral center. Patients were excluded if they had craniotomy for non-metastatic lesions, radiation necrosis, or skull metastases only. The primary outcome was to define factors that predicted mortality at 90 days. Secondary measures were mFI-11 and RPA classifications. Multivariable logistic regression analyses were conducted to identify the clinically and statistically relevant predictors for the predicted mortality at 90 days with the creation cohort (n = 548). The metric developed was validated with the new data (validation cohort, n = 318), and was compared its prediction performance with secondary measures.

RESULTS

866 consecutive patients (n = 548 creation cohort, n = 318 validation cohort) were reviewed and analyzed. Score factors included in the MBLS were: age > 65 (OR 1.97 (95%CI 1.19-3.02)), presence of supra- and infratentorial metastases (OR 1.696 (1.04-2.78)); hemorrhagic metastasis (OR 1.699 (1.09-2.64)); chronic opiate use (OR 2.34 (1.43-3.84)); poor functional status (OR 1.90 (1.22-2.97)); and presence of deep brain/brainstem lesions (OR 2.01 (1.07-3.78)). 61/164 (37.2%) creation cohort patients and 51/116 (43.9%) validation cohort patients with MBLS score ≥ 3 were deceased at 3 months. High-risk patients in the creation cohort were significantly more likely to be deceased 3 months postoperatively (OR 3.699 (95%CI 2.41-5.682), P < 0.001). In the validation cohort, MBLS was highly predictive (OR 5.311 (95%CI 3.06-9.22), P < 0.001) with a c-statistic of 0.696.

CONCLUSIONS

The MBLS provides "high-risk" surgical categorization for brain metastasis patients. By using preoperative characteristics obtainable from imaging and chart review, it can be utilized in preoperative discussions, giving a clearer view of potential postoperative course and outcome.