Prevalence of prostatic calcification subtypes and association with prostate cancer

68Ga-bisphosphonates for the imaging of extraosseous calcification by positron emission tomography

Radiolabelled bisphosphonates (BPs) and [18F]NaF (18F-fluoride) are the two types of radiotracers available to image calcium mineral (e.g. bone), yet only [18F]NaF has been widely explored for the non-invasive molecular imaging of extraosseous calcification (EC) using positron emission tomography (PET) imaging. These two radiotracers bind calcium mineral deposits via different mechanisms, with BPs chelating to calcium ions and thus being non-selective, and [18F]NaF being selective for hydroxyapatite (HAp) which is the main component of bone mineral. Considering that the composition of EC has been reported to include a diverse range of non-HAp calcium minerals, we hypothesised that BPs may be more sensitive for imaging EC due to their ability to bind to both HAp and non-HAp deposits. We report a comparison between the 68Ga-labelled BP tracer [68Ga]Ga-THP-Pam and [18F]NaF for PET imaging in a rat model of EC that develops macro- and microcalcifications in several organs. Macrocalcifications were identified using preclinical computed tomography (CT) and microcalcifications were identified using µCT-based 3D X-ray histology (XRH) on isolated organs ex vivo. The morphological and mineral analysis of individual calcified deposits was performed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). PET imaging and ex vivo analysis results demonstrated that while both radiotracers behave similarly for bone imaging, the BP-based radiotracer [68Ga]Ga-THP-Pam was able to detect EC more sensitively in several organs in which the mineral composition departs from that of HAp. Our results strongly suggest that BP-based PET radiotracers such as [68Ga]Ga-THP-Pam may have a particular advantage for the sensitive imaging and early detection of EC by being able to detect a wider array of relevant calcium minerals in vivo than [18F]NaF, and should be evaluated clinically for this purpose.

Intraprostatic calcification and biochemical recurrence in men treated with cesium-131 prostate brachytherapy

PURPOSE

Baseline intraprostatic calcification (IC) has been shown to be associated with a higher rate of biochemical recurrence (BCR) in men treated with iodine-125 prostate brachytherapy (PB). We evaluated this association in a cohort of men treated with cesium-131 PB.

METHODS AND MATERIALS

We retrospectively reviewed the charts of all low- and intermediate-risk prostate cancer patients treated with cesium-131 PB +/- external beam radiotherapy (EBRT) at our institution from 2/2011 to 7/2018. Patients with < 24 months of follow up or those who received androgen deprivation therapy were excluded. Baseline IC status (defined as one or more ICs ≥ 5 mm) was determined on post-PB CT scans. Cox analysis was used to assess predictors of BCR and Kaplan-Meier survival curves were calculated.

RESULTS

Two hundred and sixteen low- and intermediate-risk prostate cancer patients treated with cesium-131 PB +/- EBRT were included. Median follow up was 56.9 months (range 24.1-111.4). Overall, 76 (35.2%) patients had baseline IC and 140 (64.8%) did not. Baseline disease characteristics did not differ significantly between groups. On univariate Cox analysis, only risk group (p = 0.047) and initial PSA (p = 0.016) were significant predictors of BCR, whereas baseline IC was not (p = 0.11). The 5-year BCR-free survival in patients with versus without baseline IC was 97.7% versus 93.8% (p = 0.405), respectively.

CONCLUSIONS

In a cohort of low- and intermediate-risk prostate cancer patients treated with cesium-131 PB, the rate of BCR in men with baseline IC was low and baseline IC was not associated with a higher risk of BCR.

Prostatic calcifications: Quantifying occurrence, radiodensity, and spatial distribution in prostate cancer patients

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Intraprostatic calcifications are under-recognized and under-reported in imaging.

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Intraprostatic calcifications are common in patients with prostate cancer.

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They commonly occur within tumors or in the vicinity of tumors.

Background

To evaluate the prevalence, density, and distribution of prostate calcification in patients with prostate cancer.

Methods

Patients who underwent both Gallium-68 PSMA PET/CT and MRI of the prostate over the course of a year were selected for analysis. The CT images with visible calcifications within the prostate were included and calcifications automatically isolated using a threshold of 130 HU. The corresponding multiparametric MRI was assessed and the peripheral zone, transition zone, MRI-visible tumor, and urethra manually contoured. The contoured MRI and CT images were registered using rigid registration, and calcifications mapped automatically to the MRI contours.

Results

A total of 85 men (age range 50–88, mean 69 years, standard deviation 7.2 years) were assessed. The mean serum Prostate Specific Antigen PSA was 16.7, range 0.12 to 94.4. Most patients had intermediate-risk disease (68%; Gleason grade group 2 and 3), 26% had high-risk disease (Gleason grade group 4 and 5), and 6% had low-risk disease (Gleason grade group 1). Forty-six patients out of 85 (54%) had intraprostatic calcification. Calcification occurred more in transition zone than the peripheral zone (65% vs. 35%). The mean density of the calcification was 227 HU (min 133, max 1,966 HU). In 12 patients, the calcification was within an MRI-visible tumor, in 24 patients, there were calcifications within a 9 mm distance of the tumor border, and in 9 patients, there were calcifications located between the urethra and tumor.

Conclusions

Calcifications are common in patients with prostate cancer. Their density and location may make them a significant consideration when planning treatment or retreatment with some types of minimally invasive therapy.

Abiraterone acetate preferentially enriches for the gut commensal Akkermansia muciniphila in castrate-resistant prostate cancer patients

Abiraterone acetate (AA) is an inhibitor of androgen biosynthesis, though this cannot fully explain its efficacy against androgen-independent prostate cancer. Here, we demonstrate that androgen deprivation therapy depletes androgen-utilizing Corynebacterium spp. in prostate cancer patients and that oral AA further enriches for the health-associated commensal, Akkermansia muciniphila. Functional inferencing elucidates a coinciding increase in bacterial biosynthesis of vitamin K2 (an inhibitor of androgen dependent and independent tumor growth). These results are highly reproducible in a host-free gut model, excluding the possibility of immune involvement. Further investigation reveals that AA is metabolized by bacteria in vitro and that breakdown components selectively impact growth. We conclude that A. muciniphila is a key regulator of AA-mediated restructuring of microbial communities, and that this species may affect treatment response in castrate-resistant cohorts. Ongoing initiatives aimed at modulating the colonic microbiota of cancer patients may consider targeted delivery of poorly absorbed selective bacterial growth agents.

Abiraterone acetate (AA) is indicated for the treatment of patients with metastatic castrate-resistant prostate cancer. Here, the authors show that, in prostate cancer patients, orally administered AA remodels the gut microbiome and promotes the enrichment of the commensal bacterium Akkermansia muciniphila at the expense of androgen-utilizing Corynebacterium species.

On the chemical composition of psammoma bodies microcalcifications in thyroid cancer tissues

Recently the knowledge of chemical composition of pathological mineralizations is an important topic extensively studied because it could give more in-depth information to understand pathologies themselves and to improve prevention methods. In this work, psammoma bodies (PBs) microcalcifications in thyroid cancer tissue are investigated by different and complementary analytical methods as: micro-Fourier transformed spectroscopy, X-ray fluorescence spectroscopy, Inductively Coupled plasma Optical Emission Spectroscopy (ICP-OES) and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy imaging (EDX). For the first time the micro-FTIR analysis of the only inorganic phase isolated from PBs was reported. Signals of the recorded spectrum showed that the main component of the calcifications is the amorphous carbonated calcium phosphate, and the IR spectrum of thyroid PBs is strongly consistent with that of PBs in human ovarian tumors. The XRF and the ICP analysis detected also the presence of iron ad zinc in thyroid PBs. These results are validated by scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy imaging (EDX) carried out on tissue samples of the papillary thyroid carcinoma. By these analytical methods magnesium and sodium were detected within PBs while the presence of iron was confirmed by the Perls test. Summarizing the results of applied analytical methods, the main detected elements within the thyroid psammoma bodies are Ca, P, Mg, Na, Fe and Zn. Magnesium and sodium are found in malignant breast cancer microcalcifications, thus they seem correlated to neoplastic transformation. The Fe and Zn elements could give information about the origin of these pathological microcalcifications.

Pathological Mineralization: The Potential of Mineralomics

Pathological mineralization has been reported countless times in the literature and is a well-known phenomenon in the medical field for its connections to a wide range of diseases, including cancer, cardiovascular, and neurodegenerative diseases. The minerals involved in calcification, however, have not been directly studied as extensively as the organic components of each of the pathologies. These have been studied in isolation and, for most of them, physicochemical properties are hitherto not fully known. In a parallel development, materials science methods such as electron microscopy, spectroscopy, thermal analysis, and others have been used in biology mainly for the study of hard tissues and biomaterials and have only recently been incorporated in the study of other biological systems. This review connects a range of soft tissue diseases, including breast cancer, age-related macular degeneration, aortic valve stenosis, kidney stone diseases, and Fahr’s syndrome, all of which have been associated with mineralization processes. Furthermore, it describes how physicochemical material characterization methods have been used to provide new information on such pathologies. Here, we focus on diseases that are associated with calcium-composed minerals to discuss how understanding the properties of these minerals can provide new insights on their origins, considering that different conditions and biological features are required for each type of mineral to be formed. We show that mineralomics, or the study of the properties and roles of minerals, can provide information which will help to improve prevention methods against pathological mineral build-up, which in the cases of most of the diseases mentioned in this review, will ultimately lead to new prevention or treatment methods for the diseases. Importantly, this review aims to highlight that chemical composition alone cannot fully support conclusions drawn on the nature of these minerals.

Do dietary calcium and vitamin D matter in men with prostate cancer?

Active surveillance (AS) is an attractive alternative to immediate treatment for men with low-risk prostate cancer. Thus, the identification of environmental factors that promote the progression of indolent disease towards aggressive stages is critical to optimize clinical management. Epidemiological studies suggest that calcium-rich diets contribute to an increased risk of developing prostate cancer and that vitamin D reduces this risk. However, the potential effect of these nutrients on the progression of early-stage prostate tumours is uncertain, as studies in this setting are scarce and have not provided unambiguous conclusions. By contrast, the results of a preclinical study from our own group demonstrate that a diet high in calcium dose-dependently accelerated the progression of early-stage prostate tumours and that dietary vitamin D prevented this effect. The extent to which the conclusions of preclinical and epidemiological studies support a role for calcium and vitamin D and the relevance of monitoring and adjustment of calcium and/or vitamin D intake in patients on AS require further investigation.

Microcalcifications, calcium-sensing receptor, and cancer

Calcium stones and calculi are observed in numerous human tissues. They are the result of deposition of calcium salts and are due to high local calcium concentrations. Prostatic calculi are usually classified as endogenous or extrinsic stones. Endogenous stones are commonly caused by obstruction of the prostatic ducts around an enlarged prostate resulting from benign prostatic hyperplasia or from chronic inflammation. The latter occurs mainly around the urethra and is generally caused by reflux of urine into the prostate. Calcium concentrations higher than in the plasma at sites of infection may induce the chemotactic response that eventually leads to recruitment of inflammatory cells. The calcium sensing receptor (CaSR) may be crucial for this recruitment as its expression and activity are increased by cytokines such as IL-6 and high extracellular calcium concentrations, respectively. The links between calcium calculi, inflammation, calcium supplementation, and CaSR functions in prostate cancer patients will be discussed in this review.

Observed high incidence of prostatic calculi with the potential to act as natural fiducials for prostate image guided radiotherapy

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Prostatic calculi are a frequent radiological finding and may aid prostate IGRT.

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Incidence of prostatic calculi in a population of radiotherapy patients is reported.

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Significant proportion of patients have calculi detectable on radiotherapy images.

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Prostatic calculi may reduce the need for surgically implanted markers.

Purpose

This study aims to quantify the incidence and distribution of prostatic calculi in a population of prostate radiotherapy patients and assess their potential role in prostate image guided radiotherapy (IGRT).

Methods & materials

A retrospective analysis of trans-rectal ultrasound (TRUS), computed tomography (CT) planning and treatment verification cone beam CT (CBCT) scans from radical prostate radiotherapy patients (external beam and brachytherapy) between 2012 and 2014 was undertaken by a single experienced observer. An internationally validated schema from the Prostate Imaging Reporting and Data system (PIRADS) was used to map the location of calculi. The association of calculi with patient and disease characteristics was explored. Data was analysed using SPSS (IBM version 22.0) using descriptive statistical methods and logistic binary regression analysis.

Results

389 scan sets from 254 patients were included in the analysis. The overall incidence of calculi was 85% (n = 218) of which 79% (n = 201) were intra-prostatic calculi. The mean number of intra-prostatic calculi was 2 (range 1–10) and the mean size of calculi was 3.7 mm (range 0.5–15 mm). Calculi were most frequently observed in the posterior of the mid-gland (PI-RADs 3p, 9p) and posterior of the apex (PI-RADs 5p, 11p). 99% (n = 135) of CT planning scans with a corresponding CBCT had calculi in the same PIRADs location and all calculi were visible at the last fraction. There was no statistically significant association of calculi and N stage, M stage or Gleason score.

Conclusions

A significant proportion of prostate radiotherapy patients have prostatic calculi detectable on pre radiotherapy imaging. Calculi observed on CT were also detectable on CBCT in 99% of cases and remain visible at the end of treatment. These findings add to the growing evidence base supporting the potential of calculi as an alternative to fiducial markers to aid prostate IGRT.

Ultrasound detection of prostatic calculi as a parameter to predict the appearance of hematospermia after a prostate biopsy

Purpose:

We evaluated the correlation between prostate calculi and hematospermia in patients undergoing prostate biopsy, and its impact on sexual activity of patients.

Materials and Methods:

A single-center prospective randomized study of 212 patients referred for transrectal ultrasound-guided prostate biopsy (TRUSBx) was performed. All patients were divided into two groups: Group A (GA), 106 patients with moderate/marked presence of prostatic calculi visualized by TRUS; Group B (GB), 106 patients with absence/scarce of prostatic calcifications. Patients were handed questionnaires to obtain a validated data on the duration and impact of hematospermia on sexual activity. The anxiety scores were recorded using a visual analogue scale.

Results:

No significant difference was noted between the two groups when comparing age, preoperative PSA level, prostate volume, and biopsy number, except for digital rectal examination (DRE) findings. Post-biopsy results of patients included in GA revealed that the complication of hematospermia was present in 65.1%, while in GB was present in 39.7% (p<0.001).

On multivariate analysis for identifying significant preoperative predictors of hematospermia, which included variables of age, PSA, prostate volume, and prostate cancer were not shown to be significant predictors of hematospermia, except DRE and prostate calculi (p<0.001).

The mean anxiety score was 3.7±2.8 in GA and 2.3±1.9 in GB, respectively (p<0.001).

Conclusions:

Prostatic calculi are an independent predictive factor of severe hematospermia after TRUSBx on the basis of multivariate analysis, but don't affect the positive rate of prostate cancer. Patients should be adequately counselled before TRUSBx to avoid undue anxiety and alterations in sexual activity.

Prostatic Calculi: Do They Matter?

INTRODUCTION

Prostatic calculi (PC) are frequently detected at computed tomography or ultrasound in men attending the health center or the urology outpatient department. PC have attracted more attention from urologists, but the clinical significance of PC is unknown.

AIM

To review the available literature on the effects of PC on prostatic diseases and sexual function in men.

METHODS

Relevant clinical trials were identified by searching the PubMed, Embase, and Cochrane Library databases. Results were classified, summarized, and analyzed.

MAIN OUTCOME MEASURES

Transabdominal and rectal ultrasonography; urodynamics analysis; International Prostate Symptom Score; pathologic examination of prostatic tissue; prostate-specific antigen; and expressed prostatic secretion.

RESULTS

PC can not only prolong the duration of bothersome symptoms but also decrease the cure rate of antibacterial therapy in patients with chronic prostatitis. Patients with PC usually have more severe lower urinary tract symptoms (LUTS), and some studies reported that moderate to marked PC are a predisposing factor for moderate to severe LUTS. Studies also reported that the serum level prostate-specific antigen is not influenced by PC. In addition, the presence of PC is not associated with an increased risk of prostate cancer. However, the correlation between PC in the peripheral zone and prostate cancer is statistically significant. In addition, the association between PC and Gleason scores is controversial. Some novel studies suggested that PC might play an important role in sexual impairment in middle-age men or men with chronic pelvic pain syndrome or chronic prostatitis. Recently, PC were found to increase the incidence of severe LUTS, urinary retention, and hematospermia after transrectal ultrasound-guided prostate biopsy.

CONCLUSION

PC can aggravate LUTS, chronic prostatitis, and sexual dysfunction in men, but the association between PC and prostate cancer is still controversial. Cao J-J, Huang W, Wu H-S, et al. Prostatic Calculi: Do They Matter? Sex Med Rev 2018;6:482-491.

SpidermiR: An R/Bioconductor Package for Integrative Analysis with miRNA Data

Gene Regulatory Networks (GRNs) control many biological systems, but how such network coordination is shaped is still unknown. GRNs can be subdivided into basic connections that describe how the network members interact e.g., co-expression, physical interaction, co-localization, genetic influence, pathways, and shared protein domains. The important regulatory mechanisms of these networks involve miRNAs. We developed an R/Bioconductor package, namely SpidermiR, which offers an easy access to both GRNs and miRNAs to the end user, and integrates this information with differentially expressed genes obtained from The Cancer Genome Atlas. Specifically, SpidermiR allows the users to: (i) query and download GRNs and miRNAs from validated and predicted repositories; (ii) integrate miRNAs with GRNs in order to obtain miRNA-gene-gene and miRNA-protein-protein interactions, and to analyze miRNA GRNs in order to identify miRNA-gene communities; and (iii) graphically visualize the results of the analyses. These analyses can be performed through a single interface and without the need for any downloads. The full data sets are then rapidly integrated and processed locally.

Fiducial marker guided prostate radiotherapy: a review

Image-guided radiotherapy (IGRT) is an essential tool in the accurate delivery of modern radiotherapy techniques. Prostate radiotherapy positioned using skin marks or bony anatomy may be adequate for delivering a relatively homogeneous whole-pelvic radiotherapy dose, but these surrogates are not reliable when using reduced margins, dose escalation or hypofractionated stereotactic radiotherapy. Fiducial markers (FMs) for prostate IGRT have been in use since the 1990s. They require surgical implantation and provide a surrogate for the position of the prostate gland. A variety of FMs are available and they can be used in a number of ways. This review aimed to establish the evidence for using prostate FMs in terms of feasibility, implantation procedures, types of FMs used, FM migration, imaging modalities used and the clinical impact of FMs. A search strategy was defined and a literature search was carried out in Medline. Inclusion and exclusion criteria were applied, which resulted in 50 articles being included in this review. The evidence demonstrates that FMs provide a more accurate surrogate for the position of the prostate than either external skin marks or bony anatomy. A combination of FM alignment and soft-tissue analysis is currently the most effective and widely available approach to ensuring accuracy in prostate IGRT. FM implantation is safe and well tolerated. FM migration is possible but minimal. Standardization of all techniques and procedures in relation to the use of prostate FMs is required. Finally, a clinical trial investigating a non-surgical alternative to prostate FMs is introduced.