Multiparametric MRI in the management of prostate cancer: an update-a narrative review

Autonomous Tumor Signature Extraction Applied to Spatially Registered Bi-Parametric MRI to Predict Prostate Tumor Aggressiveness: A Pilot Study

BACKGROUND

Accurate, reliable, non-invasive assessment of patients diagnosed with prostate cancer is essential for proper disease management. Quantitative assessment of multi-parametric MRI, such as through artificial intelligence or spectral/statistical approaches, can provide a non-invasive objective determination of the prostate tumor aggressiveness without side effects or potential poor sampling from needle biopsy or overdiagnosis from prostate serum antigen measurements. To simplify and expedite prostate tumor evaluation, this study examined the efficacy of autonomously extracting tumor spectral signatures for spectral/statistical algorithms for spatially registered bi-parametric MRI.

METHODS

Spatially registered hypercubes were digitally constructed by resizing, translating, and cropping from the image sequences (Apparent Diffusion Coefficient (ADC), High B-value, T2) from 42 consecutive patients in the bi-parametric MRI PI-CAI dataset. Prostate cancer blobs exceeded a threshold applied to the registered set from normalizing the registered set into an image that maximizes High B-value, but minimizes the ADC and T2 images, appearing "green" in the color composite. Clinically significant blobs were selected based on size, average normalized green value, sliding window statistics within a blob, and position within the hypercube. The center of mass and maximized sliding window statistics within the blobs identified voxels associated with tumor signatures. We used correlation coefficients (R) and p-values, to evaluate the linear regression fits of the z-score and SCR (with processed covariance matrix) to tumor aggressiveness, as well as Area Under the Curves (AUC) for Receiver Operator Curves (ROC) from logistic probability fits to clinically significant prostate cancer.

RESULTS

The highest R (R > 0.45), AUC (>0.90), and lowest p-values (<0.01) were achieved using z-score and modified registration applied to the covariance matrix and tumor signatures selected from the "greenest" parts from the selected blob.

CONCLUSIONS

The first autonomous tumor signature applied to spatially registered bi-parametric MRI shows promise for determining prostate tumor aggressiveness.

Technical note: hydrogel-based mimics of prostate cancer with matched relaxation, diffusion and kurtosis for validating multi-parametric MRI

BACKGROUND

Protocol standardization and optimization for clinical translation of emerging quantitative multiparametric (mp)MRI biomarkers of high-risk prostate cancer requires imaging references that mimic realistic tissue value combinations for bias assessment in derived relaxation and diffusion parameters.

PURPOSE

This work aimed to develop a novel class of hydrogel-based synthetic materials with simultaneously controlled quantitative relaxation, diffusion, and kurtosis parameters that mimic in vivo prostate value combinations in the same spatial compartment and allow stable assemblies of adjacent structures.

METHODS

A set of materials with tunable T2, diffusion, and kurtosis were assembled to create quantitative biomimetic (mp)MRI references. T2 was controlled with variable agarose concentration, monoexponential diffusion by polyvinylpyrrolidone (PVP), and kurtosis by addition of lamellar vesicles. The materials were mechanically stabilized by UV cross-linked polyacrylamide gels (PAG) to allow biomimetic morphologies. The reference T2 were measured on a 3T scanner using multi-echo CPMG, and diffusion kurtosis-with multi-b DWI.

RESULTS

Agarose concentration controls T2 values which are nominally independent of PVP or vesicle concentration. For agarose PVP hydrogels, monoexponential diffusion values are a function of PVP concentration and independent of agarose concentration. Compared to free vesicles, for agarose-PAG combined with vesicles, diffusion was predominantly controlled by vesicles and PAG, while kurtosis was affected by agarose and vesicle concentration. Both hydrogel classes achieved image voxel parameter values (T2, Da, Ka) for relaxation (T2: 65-255 ms), apparent diffusion (Da: 0.8-1.7 μm2/ms), and kurtosis (Ka: 0.5-1.25) within the target literature ranges for normal prostate zones and cancer lesions. Relaxation and diffusion parameters remained stable for over 6 months for layered material assemblies.

CONCLUSION

A stable biomimetic mpMR reference based on hydrogels has been developed with a range of multi-compartment diffusion and relaxation parameter combinations observed in cancerous and healthy prostate tissue.

Clinical efficacy of prostate PI-RADS V2.1 score combined with serum PSA-related indicators in the detection of gray zone prostate cancer

PURPOSE

The purpose of this study is to improve the diagnostic accuracy of gray zone prostate cancer evaluation by combining the prostate imaging report and data system version 2.1 (PI-RADS V2.1) score with serum prostate-specific antigen (PSA).

METHODS

We analyzed data from 212 men suspected of having prostate cancer and compared PSA-related indicators and PI-RADS V2.1 scores between 96 patients with prostate cancer and 116 without prostate cancer. By contrasting PI-RADS V2.1 scores with serum PSA-related markers, the diagnostic precision in the detection of grey zone prostate cancer was assessed.

RESULTS

The median PI-RADS V2.1 scores and serum tPSA levels of patients with prostate cancer were significantly higher (P < 0.05). The PI-RADS V2.1 score correlated positively with serum tPSA, PSA density (PSAD), and prostate health index (PHI) levels (P < 0.05) and negatively correlated with fPSA/tPSA concentrations (P < 0.05). Logistic regression identified risk factors including family history, PI-RADS V2.1 score, tPSA, PSAD, and PHI, with prostate volume and fPSA/tPSA as protective factors (P < 0.05). Combining serum PSA-related indicators with the PI-RADS V2.1 score improved diagnostic accuracy for gray zone prostate cancer (AUC 0.986, specificity 99.14%, sensitivity 92.71%).

CONCLUSION

The presence of a family history, a high PI-RADS V2.1 score, and elevated serum PSA-related markers contribute to high prostate cancer risk and development. The combined use of these indicators offers superior predictive value in detecting prostate cancer compared to a single indicator.

Impact of modifiable lifestyle risk factors for prostate cancer prevention: a review of the literature

Introduction

Although prostate cancer (PCa) is one of the most common cancers among men, the impact of modifiable risk and protective factors is still being debated. This review aims to qualitatively summarize the most recent studies related to potential healthy lifestyle factors affecting the development of PCa.

Methods for data acquisition

The literature focusing on modifiable risk factors for prostate cancer was reviewed. Medline and Embase via the Ovid database were searched, and all relevant and inherent articles were analyzed. Non-eligible publications, such as review articles, editorials, comments, guidelines, or case reports, were excluded.

Synthesis of the evidence obtained from data analysis

This review confirms that there is strong evidence that being overweight or obese increases the risk of advanced prostate cancer (assessed by body mass index (BMI), waist circumference, and waist-hip ratio), particularly considering central adiposity and ethnicity as contributing factors. The possible contribution of smoking still seems not entirely clear, while alcohol seems to affect PCa prevention in patients taking 5α-reductase inhibitors (5-ARIs). Dietary fibers may have anti-inflammatory properties and improve insulin sensitivity by reducing IGF bioactivity. In particular, dietary fiber intake like insoluble and legume fibers may be inversely associated with prostate cancer risk. Also, hyperglycemia and hyperinsulinemia, with untreated diabetic fasting blood glucose levels, could be modifiable prostate cancer risk factors. In two studies, aspirin was associated with a lower risk of lethal PCa and overall mortality. Concerning the role of vitamins, despite conflicting and divergent results, serum retinol concentration seems to be associated with an increased risk of prostate cancer and high-grade prostate cancer. Some studies resulted in disagreement about the role of selenium and vitamin E. We found inconsistent and controversial findings about the association between vitamin D and prostate cancer risk.

Conclusion

Far from being conclusive evidence, our findings confirm some strong evidence already found in the previous literature and highlight the need to clarify the role of some risk factors whose role is not yet completely known. This effort would facilitate the cultural and social change that may allow the shift from the treatment of prostate cancer when diagnosed to the real efforts needed for systematic prevention.

Percutaneous Radiofrequency Ablation (RFA) in renal cancer. How to manage challenging masses. A narrative review

In the last decades, the refinements in the imaging techniques led to an increased number of detected renal tumors. If radical and partial nephrectomy remain the gold standard for the treatment of renal cancer, Radio-Frequency Ablation (RFA) has emerged as a therapeutic option for renal masses. Even if this technique is minimally-invasive, it requires a proper preoperative anatomic study and in some cases RFA treatment is technically challenging. To date, there is no standardization for studying challenging cases before treatment and to plan a safe and effective procedure when intervening organs are in the trajectory of the needle. In this study we searched the literature focusing on the challenging cases and strategy applied to manage the treatment safely and effectively.

MATERIALS AND METHODS

MedLine and Embase via Ovid database were searched, using the following key words: Percutaneous RFA, radiofrequency, renal ablation, kidney ablation, renal thermoablation, kidney thermoablation, hydrodissection, heat sink. The difficulties found in the literature while performing the ablation procedure were grouped and a categorization of the strategies applied to perform a safe and effective procedure was proposed, in the aim to standardize the approach for treatment of challenging cases. Literature was analyzed according with selection criteria agreed by the Authors.

RESULTS

The literature review showed four groups of lesions requiring an experienced approach. Group 1: Lesions close to the bowel. Group 2: Lesions close to the urinary tract. Group 3: Lesions close to intervening organs. Group 4: Lesions close to large vessels (heat-sink phenomenon).

CONCLUSION

When planning a RFA treatment, a standardized approach to challenging masses is possible. This review make the treatment of these masses more systematic and safe.

Oncologic outcome of salvage high-intensity focused ultrasound (HIFU) in radiorecurrent prostate cancer. A systematic review

INTRODUCTION

External Beam Radiation Therapy (EBRT) is one of the option available for the treatment of clinically localized prostate cancer. In patients with radiorecurrent localized prostate cancer, Androgen Deprivation Therapy (ADT) is one of the most common therapeutic strategies. However, in the last decades, other salvage treatment options have been investigated, such as brachytherapy, cryoablation and High Intensity Focused Ultrasound (Hifu).

MATERIAL AND METHODS

The oncologic outcome of Hifu in a salvage setting after EBRT failure was investigated. We reviewed the literature from 2005 to 2020 in order to report the oncologic outcome of the technique.

RESULTS

A total of 1241 patients were analyzed, with a mean age of 68.6 years and a PSA value of 5.87 ng/mL before treatment. Mean follow-up was 24.3 months after treatment, ranging from 3 to 168 months.

CONCLUSION

Our review of the literature revealed that salvage Hifu is effective in the treatment of radiorecurrent clinically localized prostate cancer, with an overall survival of 85.2% at 5 years.

PSA-IgM and iXip in the diagnosis and management of prostate cancer: clinical relevance and future potential. A review

The Prostate Specific Antigen (PSA) is the first filter in the diagnosis of prostate cancer. Unfortunately, it is organ-specific but not cancer-specific. In addition, some prostate cancers are not clinically-significant and their diagnosis and treatment may lead to overdiagnosis and overtreatment. For these reasons, other markers have been proposed in the last years, such as PCA3 and PHI, but none of these are currently used in the clinical practice on large scale. In the last decade, PSA-IgM and the algorithm iXip have emerged for the diagnosis of prostate cancer and showed to perform well in decreasing the detection of clinically-insignificant prostate cancer and in reducing the number of unnecessary prostate biopsies. This review focuses on data reported in the literature on PSA-IgM and iXip as well as on the future perspectives of their usage in the clinical practice on large scale.

Oncologic outcome of salvage high-intensity focused ultrasound (HIFU) in radiorecurrent prostate cancer. A systematic review

INTRODUCTION

External Beam Radiation Therapy (EBRT) is one of the option available for the treatment of clinically localized prostate cancer. In patients with radiorecurrent localized prostate cancer, Androgen Deprivation Therapy (ADT) is one of the most common therapeutic strategies. However, in the last decades, other salvage treatment options have been investigated, such as brachytherapy, cryoablation and High Intensity Focused Ultrasound (Hifu).

MATERIAL AND METHODS

The oncologic outcome of Hifu in a salvage setting after EBRT failure was investigated. We reviewed the literature from 2005 to 2020 in order to report the oncologic outcome of the technique.

RESULTS

A total of 1241 patients were analyzed, with a mean age of 68.6 years and a PSA value of 5.87 ng/mL before treatment. Mean follow-up was 24.3 months after treatment, ranging from 3 to 168 months.

CONCLUSION

Our review of the literature revealed that salvage Hifu is effective in the treatment of radiorecurrent clinically localized prostate cancer, with an overall survival of 85.2% at 5 years.