Circulating tumor cells as a recurrence risk marker in glioma: a retrospective study.

Background: Glioma is a highly aggressive brain tumor with a poor prognosis due to its infiltrative nature and frequent recurrence. Current treatments often fail to achieve long-term remission, partly because of the lack of effective biomarkers for early detection and recurrence prediction. Circulating tumor cells (CTCs) have emerged as potential biomarkers in various cancers, but research on CTC detection in glioma is relatively limited, and its clinical application remains in the exploratory phase. This study aimed to characterize peripheral blood CTC as a biological biomarker for recurrence risk in glioma, laying the groundwork for prospective validation. Methods: CTCs were isolated, identified, and quantified using the CanPatrol technique in 27 patients with glioma and 10 benign brain lesion controls. The relationship between CTCs and World Health Organization (WHO) grade, as well as glioma recurrence, was analyzed based on the expression of epithelial and mesenchymal markers. Results: The positive rate of CTCs was higher in patients with high-grade glioma (WHO grade III-IV) than in those with low-grade glioma (WHO grade I-II). The positive rate of CTCs in patients with high Ki-67 expression in primary tumor tissues was significantly higher than in those with low Ki-67 expression (P=0.01). Additionally, CTC-positive cases showed a recurrence rate of 93% (14/15) versus 63% (5/8) in CTC-negative cases (P=0.10). Univariate analysis identified both high Ki-67 (P=0.001) and WHO grade III-IV (P=0.002) as significant predictors of recurrence. Conclusions: The level of CTCs in the peripheral blood of patients with brain glioma is significantly correlated with both the WHO grade of tumor histology and Ki-67 expression levels. The detection of CTCs, WHO grade, and Ki-67 expression levels may have potential clinical value in predicting glioma recurrence, but prospective validation is required.