Ratio free/total PSA (%f-PSA) in men with total PSA 0.5-3 ng/ml: improvement for prostate cancer detection?

trans-Cleavage of the CRISPR-Cas12a-aptamer system for one-step antigen detection

Rapid detection of prostate-specific antigen (PSA) is pivotal for the early screening of prostate cancer (PCa). Here, we devise a one-step, amplification-free fluorescent detection strategy for PSA, employing the trans-cleavage principle of a CRISPR-Cas12a-aptamer system. This method offers a linear range of 0.31-5 ng mL-1 and a detection limit of 0.16 ng mL-1. The high-confidence quantification of PSA is demonstrated through the analysis of real samples, effectively distinguishing between PCa patients and healthy individuals.

Prevalence of prostate cancer at different levels of serum prostate-specific antigen (PSA) and different free: total PSA ratios in a consecutive series of men referred for prostate biopsies

OBJECTIVE

In this retrospective study we report on the detection rate of prostate cancer (PCa) at different levels of prostate-specific antigen in serum (s-PSA) and at different PSA ratios (free:total PSA) during a 2-year period in patients without previously known PCa.

MATERIAL AND METHODS

During the years 2001 and 2002, 361 consecutive patients were examined with ultrasound-guided core needle biopsies at our department. The patients were biopsied due to an increased s-PSA level, a low PSA ratio or findings at digital rectal examination (DRE). Patients with previously known cancer (T1a/b or cancer already detected with fine-needle aspiration cytology) were excluded. We used the BioPince biopsy needle, which has a stroke length of 32 mm. In 91% of the patients, eight biopsies were taken from the apex, mid-medial, mid-lateral and base positions bilaterally.

RESULTS

Of the 361 patients, 188 (52%) had PCa. Most cancers were T1c or T2 tumors (51% and 34%, respectively). Among patients with an s-PSA level of < 4 ng/ml, 8/35 (23%) had PCa. Five of 13 patients with a normal DRE (T1c) and an s-PSA level of < 4 ng/ml had PCa. In total, in the PSA ratio intervals 0.05-0.1 and 0.11-0.17, cancer was found in 71% and 51% of cases, respectively. In contrast, only 35% of patients had positive biopsies when the PSA ratio was normal (p<0.01).

CONCLUSIONS

The overall cancer detection rate was high and a large proportion of patients with an s-PSA level of < 4 ng/ml had PCa. The risk of having PCa increased considerably with a low PSA ratio.