Glioma (Detection of Brain Tumor Cells in the Peripheral Blood by a Telomerase Promoter-Based Assay. Kelly MacArthur et al. Cancer Res 74:2152-2159 (2014).
High-grade brain tumors are often aggressive and generally associated with poor prognosis. Standard monitoring for treatment response and disease progression in patients with high-grade glioma can present challenges. Serial MRI obtained before and following completion of therapy is typically involved, but changes resulting from either pseudoprogression or radionecrosis may mimic progressive disease, confounding therapeutic options. Given the poor prognosis, and difficulty in monitoring tumor response or progression, there is a need to develop approaches to improve tumor assessment pre-, during and post-treatment. In the study described by MacArthur et al., Liquid Biotech’s telomerase-based assay that measures CTCs was employed to monitor glioma patients. Figure 1 below, which was adapted from MacArthur et al., illustrates the approach to differentiate between progressive disease and pseudoprogression. See referenced manuscript for more detail.
Example of serial enumeration to monitor treatment response. A. CTC levels from healthy, normal volunteers. Based on these data a CTC threshold was set at 1.2 CTCs. B. CTC counts are elevated in most patients with glioma before the start of radiotherapy (Pre-RT), with marked overall decrease after treatment is complete (Post-RT). C. Comparison of CTC trends and brain axial MRI of “progressive disease” versus “pseudoprogression.” Note progressive disease CTC counts increase post-RT in the patient that does not respond to therapy (from 5.0 to 15.4 CTCs) whereas the CTC counts decrease in a patient that by MRI appears to have progressive disease but in fact has responded to therapy (from 12.5 to 1.0 CTCs).
Liquid Biotech’s telomerase-based assay is useful for the detection of brain tumors and may have utility in differentiating progressive disease from pseudoprogression.