Preoperative blood testing for glioblastoma, brain metastases, and primary central nervous system lymphoma differentiation.

Background: Differentiating glioblastoma (GBM), brain metastases, and primary central nervous system lymphoma (PCNSL) in clinical practice is difficult. This study aimed to evaluate the diagnostic value of routine blood biomarkers in patients with GBM, brain metastases, and PCNSL and find a preoperative differential diagnostic tool for these tumors. Methods: The perioperative medical records of 70 GBM, 41 PCNSL, and 81 brain metastases patients and their preoperative blood test results were compared and analyzed, and a diagnostic model to differentiate among them established. Results: Patient age, plateletcrit, international normalized ratio (INR), and thrombin time (TT) were independently associated with differential diagnosis by multinomial logistic regression. Compared with GBM patients, brain metastases patients were significantly older (OR =1.055, 95% CI: 1.016-1.094, P=0.005) and had lower plateletcrit levels (OR =0.008, 95% CI: 0.004-0.017, P=0.027). In addition, patients with GBM had lower INR and higher TT than patients with the other two tumor types. A diagnostic model including these parameters, had an accuracy of 88.2% and 76.1% for brain metastases and GBM, respectively. Conclusions: Preoperative plateletcrit, INR, and TT may be used as inexpensive blood diagnostic biomarkers for differentiating brain metastases from other intracranial malignant tumors.