A novel prostate cancer epigenetic screening test which incorporates PSA values has been found to have an accuracy of 94%
A team of UK researchers have developed a novel prostate cancer (PaC) screening test based on measurement of five chromosome conformations that were originally detected in association with advanced PaC and which, together with the prostate specific antigen (PSA) test, has a high degree of accuracy for detecting the cancer.
Prostate cancer is the second most common cancer in men and in 2020, there were just over 1.4 million new cases worldwide. Further investigations for suspected PaC are based on the results of a PSA test and the threshold has conventionally been set at 3 to 4 to differentiate between ‘normal’ and ‘abnormal’ although cancer can be present at lower PSA levels. However, while other tests have been developed, these all generally have a low positive predictive value. While imaging modalities have shown promise as screening tests, the recent PROSTAGRAM study which compared PSA test, MRI and ultrasound, found that all provided a similar level of accuracy for detecting PaC.
In the current study, researchers developed an assay based on specific chromosome conformation changes in certain genes in the blood of men with PaC. Using samples from the PROSTAGRAM study, which included men diagnosed with PaC and control patients, the team set out to establish whether their novel assay (EpiSwitch) in combination with a PSA test could improve the accuracy of PaC diagnosis.
Novel prostate cancer test performance
Samples from 109 men (88 control and 21 with PaC) were analysed. Based on a PSA cut-off level of 3 ng/mL, the test had an accuracy of 79%. The EpiSwitch test alone had an accuracy of only 64% but when the EpiSwitch test was combined with the PSA test, the accuracy was 94%.
The researchers reported that using the EpiSwitch test and the PSA level taken as a continuous variable, there was a high positive predictive (92%) and negative predictive value (94%) for the diagnosis of PaC. Although the study was based on a relatively small number of patient samples, the authors called for further studies to examine the value of the test in larger patient samples.
Pchejetski D et al. Circulating Chromosome Conformation Signatures Significantly Enhance PSA Positive Predicting Value and Overall Accuracy for Prostate Cancer Detection. Cancers 2023