Toward the End of Blind Prostate Biopsies?

Blood-Based DNA Methylation Analysis by Multiplexed OBBPA-ddPCR to Verify Indications for Prostate Biopsies in Suspected Prostate Cancer Patients

Current prostate carcinoma (PCa) biomarkers, including total prostate-specific antigen (tPSA), have unsatisfactory diagnostic sensitivity and specificity resulting in overdiagnosis and overtreatment. Previously, we described an optimised bias-based preamplification-digital droplet PCR (OBBPA-ddPCR) technique, which detects tumour DNA in blood-derived cell-free DNA (cfDNA) of cancer patients. The current study investigated the performance of newly developed OBBPA-ddPCR-based biomarkers. Blood plasma samples from healthy individuals (n = 90, controls) and PCa (n = 39) and benign prostatic hyperplasia patients (BPH, n = 40) were analysed. PCa and BPH patients had tPSA values within a diagnostic grey area of 2-15 ng/mL, for whom further diagnostic validation is most crucial. Methylation levels of biomarkers RASSF1A, MIR129-2, NRIP3, and SOX8 were found significantly increased in PCa patients compared to controls. By combining classical PCa risk factors (percentage of free PSA compared to tPSA (QfPSA) and patient's age) with cfDNA-based biomarkers, we developed PCa risk scores with improved sensitivity and specificity compared to established tPSA and QfPSA single-marker analyses. The diagnostic specificity was increased to 70% with 100% sensitivity for clinically significant PCa patients. Thus, prostate biopsies could be avoided for 28 out of 40 BPH patients. In conclusion, the newly developed risk scores may help to confirm the clinical decision and prevent unnecessary prostate biopsy.

Increased Sensitivity of Detection of RASSF1A and GSTP1 DNA Fragments in Serum of Prostate Cancer Patients: Optimisation of Diagnostics Using OBBPA-ddPCR

Identification of aberrant DNA methylation is a promising tool in prostate cancer (PCa) diagnosis and treatment. In this study, we evaluated a two-step method named optimised bias-based preamplification followed by digital PCR (OBBPA-dPCR). The method was used to identify promoter hypermethylation of 2 tumour suppressor genes RASSF1A and GSTP1 in the circulating cell-free DNA (cfDNA) from serum samples of PCa patients (n = 75), benign prostatic hyperplasia (BPH, n = 58), and healthy individuals (controls, n = 155). The PCa cohort was further subdivided into subgroups comprising (I) patients with Gleason Scores (GS) ≤ 7 (n = 55), (II) GS ≥ 8 (n = 10), and (III) patients with metastatic PCa diagnosis (n = 10). We found that RASSF1A methylation levels were significantly increased in all 3 PCa subgroups compared to the controls and BPH cohorts (p < 0.01 for all comparisons). Fractional abundances of methylated GSTP1 DNA fragments were significantly increased in subgroup III of metastatic PCa patients (p < 0.001). RASSF1A methylation analysis was found to be beneficial as a complementary biomarker where further diagnostic validation is most crucial. In combination with free PSA, RASSF1A methylation status helps to identify PCa patients with GS ≥ 8 and grey-zone total PSA values between 2-10 ng/mL. In our study, PCR biases between 80-90% were sufficient to detect minute amounts of tumour DNA with high signal-to-noise ratios as well as high analytical sensitivity and specificity. Both RASSF1A and GSTP1 exhibited strongly increased DNA methylation levels in all metastatic PCa patients. Our data indicates a superior sensitivity of epigenetic biomarker analyses in early detection of PCa metastases that should also help to improve PCa therapy.

Assessment of the value of the different variants of abnormal digital rectal examination finding in predicting carcinoma of the prostate: a preliminary report of a two-center study

Background

Digital rectal examination is a veritable tool for the clinical diagnosis and screening for carcinoma of the prostate. This study aims to assess the value of the different variables which constitute abnormal digital rectal examination (DRE) findings.

Results

Following ethical approval, one hundred and thirty-one men met the inclusion criteria and were enrolled in the study. The peak incidence of abnormal DRE finding was in the 8th decade of life, while the PPV was 66.5%. Of the total, 44 (33.5%) were nodular hyperplasia, 12 (9.2%) were prostate intra-epithelia neoplasia, while 75 (57.3%) were adenocarcinoma. With a positive predictive value (PPV) of 73.3%, a hard nodular feel was the only abnormal DRE finding that independently and significantly predicted the risk of prostatic adenocarcinoma. A suspicious nodule and obliterated median groove had PPV of 23.1% and lobar asymmetry, 0%. There was a statistically significant correlation (P = 0.005) between DRE findings and histology, between PSA and histology (P = 0.000) and between the size of the prostate and PSA value (P = 0.021). The mean size of the prostate was 101.2 g, standard deviation 92.11783, maximum 648 g and minimum 13.6 g.

Conclusion

Most of the variants of abnormal DRE findings do not sufficiently predict the risk of adenocarcinoma on their own. They need to be in combination with other DRE findings or a raised PSA to significantly predict adenocarcinoma.

Magnetic resonance imaging-transrectal ultrasound image fusion guidance of prostate biopsies: current status, challenges and future perspectives

The use of multiparametric magnetic resonance imaging (mpMRI) in prostate cancer (PCa) diagnosis is rapidly evolving to try to overcome the limitations of the current diagnostic pathway using systematic transrectal ultrasound-guided biopsies (TRUS_bx) for all men with clinical suspicion of PCa. Prostate mpMRI allows for high quality lesion detection and characterization and has been shown to improve detection of significant PCa with a more accurate Gleason score grading. Suspicious lesions can be stratified by suspicion and sampled by selective MRI-guided targeted biopsies (TBx) for improved diagnostic accuracy. Several TBx methods have been established and include MRI/TRUS image fusion biopsies (cognitive or software-assisted) and in-bore biopsies, but none have yet proven superior in clinical practice. However, while MRI in-bore biopsy is not routinely used due to its costs and limited availability, MRI/TRUS image fusion is rapidly embraced as it allows skilled urologists to perform TBx in an outpatient clinic. Furthermore, it gives the operator the advantage of adding TBx to the systematic standard biopsy scheme, which is the currently recommended approach. With the anticipated increased future use of prebiopsy mpMRI, a more widespread implementation of MRI/TRUS image fusion platforms is concurrently expected in clinical practice. Therefore, the objective of this review is to assess the current status, challenges and future perspectives of prostate MRI/TRUS image fusion biopsies.

Multiparametric MRI in men with clinical suspicion of prostate cancer undergoing repeat biopsy: a prospective comparison with clinical findings and histopathology

Background Multiparametric magnetic resonance imaging (mpMRI) can improve detection of clinically significant prostate cancer (csPCa). Purpose To compare mpMRI score subgroups to systematic transrectal ultrasound-guided biopsies (TRUS_bx) and prostate-specific antigen (PSA)-based findings for detection of csPCa in men undergoing repeat biopsies. Material and Methods MpMRI was performed prior to re-biopsy in 289 prospectively enrolled patients. All underwent repeat TRUS_bx followed by targeted biopsies (MRI_TB) of any mpMRI-identified lesion. MpMRI suspicion grade, PSA level, and density (PSAd) were compared with biopsy results and further matched to the radical prostatectomy (RP) specimen if available. Results PCa was detected in 128/289 (44%) patients with median age, PSA, and prior negative TRUS_bx of 64 (interquartile range [IQR] = 59-67), 12.0 ng/mL (IQR = 8.3-19.1), and 2 (IQR = 1-3), respectively. TRUS_bx detected PCa in 108/289 (37%) patients, of which 49 (45%) had insignificant cancer. MRI_TB was performed in 271/289 (94%) patients and detected PCa in 96 (35%) with 78 (81%) having csPCa. MpMRI scores showed a high association between suspicion level and biopsy results on both lesion and patient level ( P < 0.001). MpMRI was better than PSA and PSAd ( P < 0.001) to identify patients with missed csPCa. In total, 64/128 (50%) patients underwent RP; 60/64 had csPCa. MpMRI was significantly better in predicting csPCa on RP compared with TRUS_bx ( P = 0.019) as MRI_TB and TRUS_bx correctly identified 47/60 (78%) and 35/60 (58%) patients, respectively. Conclusion MpMRI improves detection of missed csPCa and suspicion scores correlate well with biopsy and RP results on both patient and lesion level.