Application of Z-scan technique in detecting circulating free DNA for prostate cancer diagnosis and monitoring.

Prostate cancer diagnosis relies on methods like PSA testing, digital rectal exams, and biopsies. The Z-scan technique, a nonlinear optical method, may provide a new, non-invasive approach to detecting circulating free DNA (ccfDNA) in serum, offering potential improvements in cancer diagnosis and monitoring. The aim of this study is to evaluate whether the Z-scan technique can serve as an alternative or complementary diagnostic tool to existing prostate cancer tests. The Z-scan technique was applied to detect apoptotic and necrotic ccfDNA fragments in the serum or plasma of prostate cancer patients. This technique measures the nonlinear refractive index's dispersive and absorptive components and was compared with laboratory data, such as PSA levels and cancer progression indicators. The study found a correlation between Z-scan-derived θ values and PSA levels, suggesting its utility in identifying cancer relapse. However, no correlation was observed with the Gleason scale. The Z-scan technique shows promise as a diagnostic and monitoring tool for prostate cancer, offering a potential non-invasive alternative to traditional methods.