Novel approaches to improve prostate cancer diagnosis and management in early-stage disease

Correlation of SUVmax and Apparent Diffusion Coefficient Values Detected by Ga-68 PSMA PET/MRI in Primary Prostate Lesions and Their Significance in Lymph Node Metastasis: Preliminary Results of an On-going Study

Objectives:

Gallium-68 (Ga-68) prostate specific membrane antigen (PSMA) positron emission tomography (PET) has been shown to be more accurate than multiparametric prostate magnetic resonance imaging (MRI) in detection of primary prostate lesions. Using hybrid PET/MRI we aim to detect the correlation between SUV_max and apparent diffusion coefficient (ADC) in primary prostate lesions and to assess their prognostic value in detection of lymph node (LN) metastasis.

Methods:

Twenty-six patients, who were diagnosed as having prostate cancer with biopsy and underwent Ga-68 PSMA PET/MRI together with biparametric prostate MRI (bpMRI) were included. SUV_max, SUV_mean and ADC were recorded for index lesions drawing a region of interest (ROI) of 1 cm² around the pixel with the highest SUV_max (ROI-1) and another ROI following borders of prostate tumor detected by bpMRI (ROI-2). Presence of LN metastasis was recorded according to PSMA PET/MRI.

Results:

SUV_max was inversely correlated with ADC (ROI-1: p=0.010; ROI-2: p=0.017 for b=800). SUV_max and SUV_means were both higher in patients with LN metastasis and ADC was lower in patients with LN metastasis for ROI-1. SUV_max cut-off value of 19.8 for ROI-1 and 20.9 for ROI-2 had sensitivity and specificity of 77.8% and 76.5%, respectively for detection of LN metastasis, whereas ADC (b=800) cut-off value of 0.92x10^-3 mm²/s had sensitivity and specificity of 87.5% and 76.5%, respectively. SUV_max/ADC (b=800) ratio increased the sensitivity and specificity to 100% and 82.4%, respectively.

Conclusion:

SUV and ADC values are inversely correlated in primary prostate lesions and the combined use of both values increases the diagnostic accuracy of hybrid PET/MRI in the detection of primary prostate lesions.

Comparison of Ga-68 PSMA positron emission tomography/computerized tomography with Tc-99m MDP bone scan in prostate cancer patients

Background/aim

The aim of our study was to compare Tc-99m MDP bone scan and Ga-68 PSMA PET/CT in terms of detection of bone metastasis in prostate cancer patients.

Materials and methods

A total of 28 prostate cancer patients with bone scan and PSMA PET/CT performed within 90 days were retrospectively included in our analysis. All bone lesions were scored as negative (score-0), positive (score-1), or suspicious (score-2) for metastasis by two experienced nuclear medicine physicians. Both patient-based and region-based analyses were made for all osseous lesions.

Results

On per-patient analysis; sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 72.7%, 52.9%, 50%, 75%, and 60.7%, respectively, for bone scan and 90.9%, 100%, 100%, 94.4%, and 96.4%, respectively, for PSMA PET/CT. On per-region analysis; sensitivity, specificity, PPV, NPV, and accuracy were 76.2%, 80.9%, 57.1%, 91.1%, and 79.8%, respectively, for bone scan and 85.7%, 100%, 100%, 95.5%, and 95.4%, respectively, for PSMA PET/CT.

Conclusion

Ga-68 PSMA PET/CT has higher sensitivity, specificity, and accuracy compared to bone scan in terms of bone metastasis detection in prostate cancer patients. Therefore, it might be the modality of choice for patients with suspicion for metastatic disease, despite negative bone scan and conventional imaging results.

Future Perspectives and Challenges of Prostate MR Imaging

MR imaging is an important part of prostate cancer diagnosis. Variations in quality and skill in general practice mean results are not as impressive as they were in academic centers. This observation provides an impetus to improve the method. Improved quality assurance will likely result in better outcomes. Improved characterization of clinically significant prostate cancer may assist in making MR imaging more useful. Improved methods of registering MR imaging with transrectal ultrasound imaging and robotic arms controlling the biopsy can reduce the impact of inexperienced operators and make the entire system of MR imaging-guided biopsies more robust.

Characterization of prostate cancer using T2 mapping at 3T: a multi-scanner study

RATIONALE AND OBJECTIVES

To assess the prostate T2 value as a predictor of malignancy on two different 3T scanners.

PATIENTS AND METHODS

Eighty-three pre-prostatectomy multiparametric MRIs were retrospectively evaluated [67 obtained on a General Electric MRI (scanner 1) and 16 on a Philips MRI (scanner 2)]. After correlation with prostatectomy specimens, readers measured the T2 value of regions-of-interest categorized as "cancers", "false positive lesions", or "normal tissue".

RESULTS

On scanner 1, in PZ, cancers had significantly lower T2 values than false positive lesions (P=0.02) and normal tissue (P=2×10(-9)). Gleason≥6 cancers had similar T2 values than false positive lesions and significantly higher T2 values than Gleason≥7 cancers (P=0.009). T2 values corresponding to a 25% and 75% risk of Gleason≥7 malignancy were respectively 132 ms (95% CI: 129-135 ms) and 77 ms (95% CI: 74-81 ms). In TZ, cancers had significantly lower T2 values than normal tissue (P=0.008), but not than false positive findings. Mean T2 values measured on scanner 2 were not significantly different than those measured on scanner 1 for all tissue classes.

CONCLUSION

All tested tissue classes had similar mean T2 values on both scanners. In PZ, the T2 value was a significant predictor of Gleason≥7 cancers.

Imaging modalities in focal therapy: patient selection, treatment guidance, and follow-up

PURPOSE OF REVIEW

Focal therapy for prostate cancer is emerging as a management option between active surveillance and radical treatments. In this article, we present two of the most important imaging modalities in focal therapy, multiparametric MRI (mpMRI) and ultrasonography. We review the recent advances within these two platforms.

RECENT FINDINGS

State-of-the-art imaging in all phases of focal therapy is essential for treatment safety. In patient selection, treatment guidance, and follow-up, different aspects of imaging are important. mpMRI is an imaging technology with high imaging resolution and contrast. This makes it an excellent technology for patient selection and treatment planning and follow-up. Ultrasound has the unique property of real-time image acquisition. This makes it an excellent technology for real-time treatment guidance. There are multiple novelties in these two platforms that have increased the accuracy considerably. Examples in ultrasound are contrast-enhanced ultrasonography, elastography, shear-wave elastography, and histoscanning. In mpMRI, these advantages consist of multiple sequences combined to one image and magnetic resonance thermometry.

SUMMARY

Standardization of multiparametric transrectal ultrasound and mpMRI is of paramount importance. For targeted treatment and follow-up, a good negative predictive value of the test is important. There is much to gain from both of these developing fields and imaging accuracy of the two platforms is comparable. Standardization in conduct and interpretation, three-dimensional reconstruction, and fusion of the two platforms can make focal therapy the standard of care for prostate cancer.

EAU standardised medical terminology for urologic imaging: a taxonomic approach

BACKGROUND

The terminology and abbreviations used in urologic imaging have generally been adopted on an ad hoc basis by different speciality groups; however, there is a need for shared nomenclature to facilitate clinical communication and collaborative research.

OBJECTIVE

This work reviews the current nomenclature for urologic imaging used in clinical practice and proposes a taxonomy and terminology for urologic imaging studies.

DESIGN, SETTING, AND PARTICIPANTS

A list of terms used in urologic imaging were compiled from guidelines published by the European Association of Urology and the American Urological Association and from the American College of Radiology Appropriateness Criteria.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Terms searched were grouped into broad categories based on technology, and imaging terms were further stratified based on the anatomic extent, contrast or phases, technique or modifiers, and combinations or fusions. Terms that had a high degree of utilisation were classified as accepted.

RESULTS AND LIMITATIONS

We propose a new taxonomy to define a more useful and acceptable nomenclature model acceptable to all health professionals involved in urology. The major advantage of a taxonomic approach to the classification of urologic imaging studies is that it provides a flexible framework for classifying the modifications of current imaging modalities and allows the incorporation of new imaging modalities. The adoption of this hierarchical classification model ranging from the most general to the most detailed descriptions should facilitate hierarchical searches of the medical literature using both general and specific terms. This work is limited in its scope, as it is not currently all-inclusive. This will hopefully be addressed by future modification as others embrace the concept and work towards uniformity in nomenclature.

CONCLUSIONS

This paper provides a noncomprehensive list of the most widely used terms across different specialties. This list can be used as the basis for further discussion, development, and enhancement.

PATIENT SUMMARY

In this paper we describe a classification system for urologic imaging terms with the aim of aiding health professionals and ensuring that the terms used are more consistent.

Primary Zonal High Intensity Focused Ultrasound for Prostate Cancer: Results of a Prospective Phase IIa Feasibility Study

OBJECTIVES

To present the results of a prospective phase IIa study assessing the role of primary zonal High Intensity Focused Ultrasound (HIFU) for prostate cancer treatment.

METHODS

31 consecutive patients with unilateral organ confined prostate cancer primarily treated by zonal HIFU (from February 2007 to June 2011) were recruited into a single centre prospective phase IIa feasibility study. Complications were prospectively recorded and graded according to the Clavien-Dindo score. Postoperatively, patients were followed with serial serum PSA determinations and digital rectal examinations. An individual PSA nadir was identified in each patient. Followup also included whole gland biopsies performed in the event of a PSA rising>2.0 ng/mL above nadir value (Phoenix criteria).

RESULTS

At a median followup of 38 months, biochemical recurrence free survival was 100%, 89%, and 82.7% at 1, 2, and 3 years, respectively, with overall and cancer specific survival of 100%. The procedure was safe and well tolerated with no major adverse events. All patients were continent at their last followup and 55.2% (16/29) had erectile function sufficient for penetration.

CONCLUSION

Primary zonal HIFU is a valid focal therapy strategy, safe and feasible in day to day practice with good promising results [corrected].

From palmistry to anthropometry: can 2nd to 4th digit length (2D:4D) predict the risk of prostate cancer?

OBJECTIVE

The 2nd to 4th digit length (2D:4D) is inversely related to androgen exposure during the fetal period, which may represent a risk factor for several steroid-related diseases. We aimed to evaluate the relationship between 2D:4D ratio and the risk of developing prostate cancer (PCa).

SUBJECTS AND METHODS

We assessed the 2D:4D ratio of 474 men >40 years old, stratified into three groups: group 1 (n = 222) patients with PCa, group 2 (n = 82) subjects with high risk of PCa, and group 3 (n = 170) men with low risk of PCa. Subjects were submitted to a digital picture of the ventral surface of the right hand and 2nd and 4th fingers measurements were determined by the distance from the proximal crease to the tip using computer-assisted analysis.

RESULTS

The mean serum prostate-specific antigen level was 7.5 ng/ml in the high-risk group and 0.92 ng/ml in the low-risk group (p < 0.05). The mean 2D:4D ratios were 0.96 ± 0.04, 0.97 ± 0.04 and 0.96 ± 0.04 for the PCa, high-risk and low-risk groups, respectively, and no difference was found among the three groups (p = 0.12).

CONCLUSION

Anthropometry of the hand using the 2D:4D ratio is not a predictor of PCa.

Integrative analysis of prostate cancer aggressiveness

BACKGROUND

Clinical management of prostate cancer (PC) is still highly demanding on the identification of robust biomarkers which will allow a more precise prediction of disease progression.

METHODS

We profiled both mRNA expression and DNA copy number alterations (CNAs) from laser capture microdissected cells from 31 PC patients and 17 patients with benign prostatic hyperplasia using Affymetrix GeneChip® technology. PC patients were subdivided into an aggressive (Gleason Score 8 or higher, and/or T3/T4 and/or N+/M+) and non-aggressive (all others) form of PC. Furthermore, we correlated the two datasets, as genes whose varied expression is due to a chromosomal alteration, may suggest a causal implication of these genes in the disease. All statistical analyses were performed in R version 2.15.0 and Bioconductor version 1.8.1., respectively.

RESULTS

We confirmed several common altered chromosomal regions as well as recently discovered loci such as deletions on chromosomes 3p14.1-3p13 and 13q13.3-13q14.11 supporting a possible role for RYBP, RGC32, and ELF1 in tumor suppression. Integrative analysis of expression and CN data combined with data retrieved from online databases propose PTP4A3 and ELF1 as possible factors for tumor progression.

CONCLUSIONS

Copy number data analysis revealed some significant differences between aggressive and non-aggressive tumors, while gene expression data alone could not define an aggressive group of patients. The assessment of CNA may have diagnostic and prognostic value in PC.

Steroid 5-alpha-reductase type 2 (SRD5A2) V89L and A49T polymorphisms and sporadic prostate cancer risk: a meta-analysis

Steroid 5-α-reductase type 2 (SRD5A2) V89L and A49T polymorphisms are thought to play a crucial role in the androgen synthesis and metabolic pathway, but their associations with prostate cancer risk remain controversial. To provide a more precise estimation of the associations between V89L and A49T polymorphisms and prostate cancer risk, we performed a meta-analysis using all published case-control studies of prostate cancer since January 1995. We used odds ratio (OR) and its 95% confidence interval (CI) to assess the strength of the association under various genetic models in both overall and stratified analyses. We also calculated the false-positive report probability, the power of the current study, and the observed P value for significant findings. This analysis included 45 eligible studies of a total of 15,562 cases and 15,385 controls, in which no significant associations were found for the V89L polymorphisms under all genetic models. However, small excess prostate cancer risk was associated with the 49T allele in mixed populations compared with the 49A allele (OR = 1.24, 95% CI = 1.02-1.50), and similar results were observed in Caucasians (OR = 1.24, 95% CI = 1.01-1.53). The sensitivity analysis further strengthened the validity of these findings without publication bias. Although there was no overall association between V89L and prostate cancer risk, A49T might play a role in the etiology of prostate cancer among Caucasians. Additional large and well-designed studies are warranted to validate these findings.

MNS16A tandem repeat minisatellite of human telomerase gene and prostate cancer susceptibility

Telomere dysfunction is an early event in the development of prostate cancer and telomerase (TERT) activity is detectable in the majority of prostate cancers. Genetic variation in TERT and its regulatory elements may influence prostate carcinogenesis. MNS16A, a functional polymorphic tandem repeat minisatellite of TERT, has been studied in several malignancies. We determined MNS16A genotypes in an Austrian case-control study for the first time in the context of prostate cancer, comprising 1165 prostate cancer cases and 674 benign prostate hyperplasia controls with PCR. In addition to the five reported variable number of tandem repeats (VNTRs), we identified VNTR-212, a rare variant, for the first time in a European population. Multiple logistic regression analysis revealed no differences in genotype distribution between cases and controls. However, in stratified analysis, MNS16A VNTR-274 (OR = 0.25, 95% CI = 0.06-0.79, P = 0.016) and genotype 274/302 (OR = 0.13, 95% CI = 0.01-0.58, P = 0.005) were associated with a significantly decreased risk of prostate cancer in the age group >70 years. Our finding of a MNS16A genotype conferring a protective effect against prostate cancer in older men suggests a potential role of this polymorphism in prostate cancer susceptibility but demands to be validated in further studies.