Parsortix System Detects Prostate Cancer in Clinical Application

The current gold standard for detection is the prostate-specific antigen (PSA) blood test, which is known to have low sensitivity and low specificity with high levels of false positives, and the digital rectal exam (DRE), which is less effective than the PSA test.

Where the PSA level is high or the DRE indicates an enlarged prostate, a solid prostate biopsy will be undertaken to detect cancer and assess the aggressiveness of the disease. This process results in many men having invasive biopsies unnecessarily.

Scientists at Barts Cancer Institute (London, UK) used a prostate cancer detection system to detect prostate cancer and to assess its aggressiveness, all through a simple blood test. This is crucial because it means that men with low level disease could avoid unnecessary and potentially harmful solid biopsy and surgical intervention instead having “active surveillance”, whereas men with an aggressive form of disease could be fast-tracked for further investigation and treatment.

The key findings of the study were that the Parsortix system (ANGLE plc; Guildford, UK) detected circulating tumor cells (CTCs) in 100% of the metastatic prostate cancer patients. The patients with localized disease included patients with early stage disease. determined by clinical investigation including the Gleason score of solid tissues taken through invasive procedures, where the decision had been taken that “active surveillance” was appropriate rather than medical intervention. Even for these earliest stage, indolent cancer patients, the Parsortix system harvested CTCs that could be detected in 75% of these patients.

The number of mesenchymal CTCs harvested by the Parsortix system was compared to the Gleason score for each of the patients and there was found to be a good correlation suggesting that Parsortix liquid biopsy may be able to provide the same or similar information as the invasive solid biopsy in assessing the aggressiveness of the cancer. The status of the patient, metastatic or localized, was analyzed against the number of mesenchymal CTCs harvested by the Parsortix system. Separately the status of the patient, metastatic or localized, was analyzed against the patient's Gleason score. Comparison of the results suggests that the Parsortix system may be able to indicate the metastatic or localized status of the patient with a higher level of accuracy than the Gleason score.

Yong-Jie Lu, MD, PhD, Reader in Medical Oncology, said, “The Parsortix system enables investigation of the mesenchymal CTCs in the patient blood and the results of our work to date suggests this has the potential to become a noninvasive liquid biopsy for prostate cancer. The exciting part of this study is the potential for the Parsortix system to be used to assess the severity of the disease as well as to detect it. This meets a key medical need to avoid over-treatment as well as to ensure treatment is available for patients who need it.” The study was presented on March 19, 2016, at the 10th ISMRC International Symposium on Minimal Residual Cancer: Liquid Biopsy in Cancer Diagnostics and Treatment held in in Hamburg (Germany).

Related Links:
Barts Cancer Institute 
ANGLE plc