Clinical Application of CTC and CTM Detection in the Diagnosis and Prognosis of Glioma

Recently, the research results cooperated by Dr. Wu?team of #YZY MED and the?teams?of well-known domestic professors were published in the Journal of Neurosurgery, the official journal of the American Association of NeuroSurgeons (AANS) (the world's No. 1 journal in the field of neurosurgery clinical research).

In this multicenter cohort study, CTC (circulating tumor cells) was detected in patients with glioma using the CTCBIOPSY system of Youzhiyou Medical. It was proved that CTC and CTM (circulating tumor microthrombus) were independent predictors of clinical diagnosis and prognosis of glioma. A large number of CTC and CTM were detected in cerebrospinal fluid of glioma patients, about 100 times that of peripheral blood. For the first time in brain gliomas, postoperative CTC levels have been demonstrated as a viable method for the assessment of MRD (minimal residual lesion).

Published by: Renmin Hospital of Wuhan University, the Second Affiliated Hospital of Nanchang University, YZY MED

Published journal: Journal of Neurosurgery（IF：4.1）

Objective: To investigate the diagnostic and prognostic value of CTC and CTM in diffuse glioma

Detection method: CTC and CTM were separated by CTCBIOPSY

Sample source: 63 patients with diffuse glioma who underwent total resection were collected, and 20 healthy patients without tumor were used as controls

?The research results:

(1) The diagnosis of CTC and CTM in glioma. The detection threshold was determined by the CTC level of healthy subjects as 2 CTCS /5ml, and the CTC positive detection rate of glioma patients was 84.13% (53/63), which was significantly higher than the CTC level of healthy subjects. The value of AUC (area under the curve, a measure of diagnostic performance) for the diagnosis of glioma based on CTCS was 0.939. CTM was more aggressive and metastatic in glioma, with a detection rate of 38.1% (24/63), and the AUC value of CTM-based diagnostic model was 0.69

(2) To explore the correlation between CTC and CTM and peripheral immunity. Analysis showed no correlation between CTC levels or CTM and peripheral immune status in diffuse glioma or GBM (glioblastoma), whereas large amounts of CTC and CTM were observed in cerebrospinal fluid of CTM-positive patients, about 100 times more than in peripheral blood, where CTM had a high similarity to parental tumors. It is speculated that CTM may be directly derived from parental tumors before entering the peripheral circulation.

(3) To explore the correlation between CTC and pathological diagnosis of glioma. Analysis showed that CTC level was significantly correlated with WHO grade, subtype, IDH status, 1p19q status and ATRX status. High CTC level represented poor prognosis of diffuse glioma, and the AUC value of GBM based on CTC level was 0.768 (threshold was 4.5/5ml). In addition, a weak negative correlation was found between CTM and KPS (Karnofsky Functional State Scale) scores (r=-0.28, P<0.05).

(4) To explore the correlation between CTC and CTM status and survival of glioma patients. Patients with low levels of CTC in diffuse glioma had significant benefit in OS (p=0.038), negative CTM was a good prognostic factor for diffuse glioma and GBM (brain glioma), and both PFS and OS were beneficial in negative CTM patients. ROC curve analysis showed that the AUC values predicted by CTM were 0.82 (6-month survival), 0.75 (1-year survival), and 0.6 (2-year survival) for diffuse glioma, and 0.81 (6-month survival), 0.87 (1-year survival), and 0.71 (2-year survival) for GBM

(5) To explore the correlation between postoperative CTC level and CTM status and treatment response. CTC tests were performed on 29 patients before and after surgery. The results showed that the positive proportion of CTM and the level of CTM increased significantly after surgery, which may promote the entry of CTM into peripheral circulation. After operation, the proportion of CTC positive decreased, but the level of CTC detection did not change significantly. Further Pearson and Spearman correlation analysis showed that postoperative CTC level was strongly correlated with P53 gene mutation (p<0.001) and KPS score (p<0.05). In addition, CTC level in GBM was closely correlated with peripheral blood lymphocyte ratio (p<0.05). Therefore, the use of postoperative CTC levels to monitor the treatment response and immune status of patients may be a promising new method.

(6) To explore the prognostic value of postoperative CTC level combined with CTM status. Survival analysis showed that high postoperative CTC levels were significantly associated with poor OS (p=0.039) in diffuse glioma, and high postoperative CTC levels were significantly associated with poor PFS (P=0.0017) and OS (P=0.00044) in GBM patients. However, surgery may result in the release of CTM and thus reduce the prognostic value of CTM, and given the prognostic importance of preoperative CTM, it may be more feasible to evaluate postoperative CTC levels and CTM together than to evaluate CTC/CTM alone. Patients were divided into a high CTC/CTM positive group (n=11) and a CTM negative group (n=18). Analysis showed that the CTM negative group showed a significant survival benefit (p=0.00067), and the high CTC/CTM positive group showed worse PFS and OS in both diffuse glioma and GBM.

Further survival analysis was conducted. After the 12 single factors were excluded by LASSO analysis, 5 factors (high postoperative CTC/CTM positive status, 1p19q co-loss, Ki-67 index, postoperative lymphocyte ratio, postoperative neutrophil/lymphocyte ratio) were finally screened for multivariate analysis. The results showed that high CTC/CTM positive status and 1p19q status were independent prognostic factors for diffuse glioma. A prognosis prediction model with high accuracy was constructed based on 5 factors (verification accuracy reached 0.895).

Finally, in the discussion section of the study, the study showed that the postoperative CTC level could predict MRD in patients, and for the first time, it was proposed that the postoperative CTC level could be used to evaluate MRD in gliomas. MRD concepts derived from leukemia, refers to the induction chemotherapy (treatment) or bone marrow transplants after complete remission, but patients still have traces of leukemia cells in the body. In recent years, circulating tumor biomarkers have been widely used in solid tumors to assess the risk of recurrence by MRD after treatment. In particular, the diffuse growth pattern of glioma makes the entire histological resection difficult, so there is an urgent need for MRD monitoring in clinical practice. Magnetic resonance imaging (MRI) has been shown not sensitive, and outside weeks circulating tumor DNA in diffuse gliomas (ctDNA) detection rate is not satisfactory. In this study, postoperative CTC levels in patients showed a significantly better survival benefit, and when combined with postoperative CTM status, CTC levels showed a significant correlation with patient survival. Several studies have shown that CTC can be used to evaluate the effect of radiotherapy and is superior to MRI in monitoring recurrence of glioma. Therefore, CTC is helpful to monitor the tumor progression of diffuse gliomas, which lays a solid theoretical foundation for the further clinical application of postoperative CTC level detection, including MRD assessment, treatment response, and tumor progression monitoring.

Reference: Qi Y, Xu Y, Yan T, et al. Use of circulating tumor cells and microemboli to predict diagnosis and prognosis in diffuse glioma. J Neurosurg. 2024 Apr 12:1-11.