Functional magnetic resonance imaging and molecular pathology at the crossroad of the management of early prostate cancer

[Role of prostate MRI, TRUS fusion biopsies and new markers in the diagnostic strategy of prostate cancer]

Multiparametric MRI prostate (mp-MRI) is a powerful tool to locate lesions>0.5cm³ (below this threshold tumor volume, prostate cancers are classified as "insignificant"). The detection rate of the mp-MRI for significant cancers of small volume (0.5-1cm³) with a Gleason score≥7 is>85 %. The prostate mp-MRI optimizes the management of cancers classified as low risk of progression by providing aggressive criteria for misclassified lesions, which require an active treatment and enhance the clinicopathological criteria of indolence for subclinical lesions, which can justify of surveillance. MRI-mp coupled to the 3D ultrasound image fusion, optimizes the predictive value of biopsies and improves tumor staging, particularly when benign prostatic hyperplasia (>40cm³) is associated with clinical course. New tissue markers feasible on biopsies allow to define better the risk of progression of the small volume of cancer in order to reinforce the indications of surveillance or delayed curative treatment.

Prostate Specific Antigen-Growth Curve Model to Predict High-Risk Prostate Cancer

PURPOSE

To investigate if a prostate specific antigen (PSA)-derived growth curve can predict the occurrence of high-risk prostate cancer (PrCA).

METHODS

Data from 38,340 men randomized to the PrCA screening arm in the prostate, lung, colorectal, and ovarian cancer screening trial (PLCO) were used to develop a PSA growth curve model to estimate PSA rate of change. The model was then used to predict high-risk PrCA in clinical data available from 680,390 veterans seeking routine care. The PSA growth curve was modeled using non-linear mixed regression and the PSA rate was estimated by taking the 1st derivative of the growth curve equation at 1 year prior to diagnosis/exit.

RESULTS

In the PLCO, PrCA incidence was 8.1%; ≈19% of whom had high-risk PrCA. Overall, a PSA rate threshold of 0.37 ng/ml/year had the best combination of sensitivity (97.2%) and specificity (97.3%) for detecting high-risk PrCA. In the VA data; 7,347 men were diagnosed with PrCA; of these 4,315 (58.7%) were diagnosed with high-risk PrCA. The PLCO optimal threshold of 0.37 ng/ml/year produced sensitivity = 95.5% and specificity = 85.2%. An optimal threshold of 0.99 ng/ml/year in AA produced sensitivity = 89.1% and specificity = 80.0%. PSA rate was a better predictor than the single last PSA value.

CONCLUSIONS

PSA growth curves predicted high-risk PrCA in the PLCO data. Fitting the same algorithm in the VA data produced lower specificity. Although encouraging, this finding underlines the need for further research to prospectively test the algorithm, especially for African-American men, the population group at highest risk of aggressive PrCA. Prostate 77:173-184, 2017. © 2016 Wiley Periodicals, Inc.

[Active surveillance for prostate cancer]

Active surveillance is part of the therapeutic possibilities of localized prostate cancer at low-risk of progression. Patients are eligible for this support modality if they meet specific criteria of indolent cancer. In this population, active surveillance will consist of a regular physical examination, monitoring of PSA and repeating prostate biopsies and/or MRI to assess the absence of evolution of the diagnosed prostate cancer. In case of modification or worsening of the monitoring criteria in favor of evolution of the cancer, the patient will be offered a deferred active treatment such as radical prostatectomy, external beam radiotherapy, brachytherapy or focal treatment. For patients still meeting the eligibility criteria, active surveillance avoids an unnecessary treatment potentially responsible of genitourinary adverse events.