Predictors of seminal vesicle invasion before radical prostatectomy

Prediction of Pathologic Findings with MRI-Based Clinical Staging Using the Bayesian Network Modeling in Prostate Cancer: A Radiation Oncologist Perspective

Purpose

This study aimed to develop a model for predicting pathologic extracapsular extension (ECE) and seminal vesicle invasion (SVI) while integrating magnetic resonance imaging-based T-staging (cTMRI, cT1c-cT3b).

Materials and Methods

A total of 1,915 who underwent radical prostatectomy between 2006-2016 met the inclusion/exclusion criteria. We performed a multivariate logistic regression analysis as well as Bayesian network (BN) modeling based on possible confounding factors. The BN model was internally validated using 5-fold validation.

Results

According to the multivariate logistic regression analysis, initial prostate-specific antigen (iPSA) (β=0.050, p<0.001), percentage of positive biopsy cores (PPC) (β=0.033, p<0.001), both lobe involvement on biopsy (β=0.359, p=0.009), Gleason score (β=0.358, p<0.001), and cTMRI (β=0.259, p<0.001) were significant factors for ECE. For SVI, iPSA (β=0.037, p<0.001), PPC (β=0.024, p<0.001), GS (β=0.753, p<0.001), and cTMRI (β=0.507, p<0.001) showed statistical significance. BN models to predict ECE and SVI were also successfully established. The overall AUC/accuracy of the BN models were 0.76/73.0% and 0.88/89.6% for ECE and SVI, respectively. According to internal comparison between the BN model and Roach formula, BN model had improved AUC values for predicting ECE (0.76 vs. 0.74; p=0.060) and SVI (0.88 vs. 0.84, p<0.001).

Conclusion

wo models to predict pathologic ECE and SVI integrating cTMRI were established and installed on a separate website for public access to guide radiation oncologists.

Development of a multiplexed urine assay for prostate cancer diagnosis

BACKGROUND

Several studies have demonstrated the value of DNA methylation in urine-based assays for prostate cancer diagnosis. However, a multicenter validation with a clinical prototype has not been published.

METHODS

We developed a multiplexed, quantitative methylation-specific polymerase chain reaction (MSP) assay consisting of 3 methylation markers, GSTP1, RARB, and APC, and an endogenous control, ACTB, in a closed-tube, homogeneous assay format. We tested this format with urine samples collected after digital rectal examination from 234 patients with prostate-specific antigen (PSA) concentrations > or =2.5 microg/L in 2 independent patient cohorts from 9 clinical sites.

RESULTS

In the first cohort of 121 patients, we demonstrated 55% sensitivity and 80% specificity, with area under the curve (AUC) 0.69. In the second independent cohort of 113 patients, we found a comparable sensitivity of 53% and specificity of 76% (AUC 0.65). In the first cohort, as well as in a combined cohort, the MSP assay in conjunction with total PSA, digital rectal examination status, and age improved the AUC without MSP, although the difference was not statistically significant. Importantly, the GSTP1 cycle threshold value demonstrated a good correlation (R = 0.84) with the number of cores found to contain prostate cancer or premalignant lesions on biopsy. Moreover, samples that exhibited methylation for either GSTP1 or RARB typically contained higher tumor volumes at prostatectomy than those samples that did not exhibit methylation.

CONCLUSIONS

These data confirm and extend previously reported studies and demonstrate the performance of a clinical prototype assay that should aid urologists in identifying men who should undergo biopsy.