"Super-active surveillance": MRI ultrasound fusion biopsy and ablation for less invasive management of prostate cancer

The State-of-the-Art and Perspectives of Laser Ablation for Tumor Treatment

Tumors significantly impact individuals' physical well-being and quality of life. With the ongoing advancements in optical technology, information technology, robotic technology, etc., laser technology is being increasingly utilized in the field of tumor treatment, and laser ablation (LA) of tumors remains a prominent area of research interest. This paper presents an overview of the recent progress in tumor LA therapy, with a focus on the mechanisms and biological effects of LA, commonly used ablation lasers, image-guided LA, and robotic-assisted LA. Further insights and future prospects are discussed in relation to these aspects, and the paper proposed potential future directions for the development of tumor LA techniques.

The role of prostate-specific antigen in light of new scientific evidence: An update in 2020

OBJECTIVE

To review and update the latest scientific evidence gathered in recent years regarding prostate-specific antigen (PSA) for better implementation into routine clinical practice.

EVIDENCE ACQUISITION

Analysis of the available evidence on the current role of PSA, based on the experience of an expert panel in the subject under analysis.

EVIDENCE SYNTHESIS

Currently, PSA cannot be considered only as a guide for the presence or absence of prostate cancer. This determination can also help the urologist to decide on the most convenient treatment for a patient with benign prostatic hypertrophy (BPH) as a criterion for disease progression, and it can also suggest the suspicious existence of a prostatic tumor when there is PSA rise of>0.3 ng/ml over the level reached 6 months after having initiated treatment with 5-alpha-reductase inhibitor. However, the limits of this PSA rise with derivatives of alternative 5-alpha-reductase (5-ARI) inhibitors to dutasteride are controversial. Moreover, PSA is a key factor for the follow-up of patients with prostate adenocarcinoma at any stage who have received treatment (surgery, radiotherapy or focal therapies, hormone therapy), it acts as a guide to identify biochemical recurrence, to suspect the existence of local or distant recurrence, as well as to propose or discard adjuvant treatments. Finally, the role of PSA as a screening tool has been recently reinforced, demonstrating increased mortality rates or the existence of more aggressive cases of prostate cancer in those countries where the use of this tool has declined.

CONCLUSIONS

We present new data about the current role of PSA in the management of patients treated for BPH and/or prostate cancer that should be implemented into routine clinical practice, with special emphasis on the relevant role of this biomarker in the screening and follow-up of prostate cancer, as well as in the progression of BPH in dutasteride treatment.

Biparametric (bp) and multiparametric (mp) magnetic resonance imaging (MRI) approach to prostate cancer disease: a narrative review of current debate on dynamic contrast enhancement

Prostate cancer is the most common malignancy in male population. Over the last few years, magnetic resonance imaging (MRI) has proved to be a robust clinical tool for identification and staging of clinically significant prostate cancer. Though suggestions by the European Society of Urogenital Radiology to use complete multiparametric (mp) T2-weighted/diffusion weighted imaging (DWI)/dynamic contrast enhancement (DCE) acquisition for all prostate MRI examinations, the real advantage of functional DCE remains a matter of debate. Recent studies demonstrate that biparametric (bp) and mp approaches have similar accuracy, but controversial evidences remain, and the specific potential benefits of contrast medium administration are still poorly discussed in literature. The bp approach is in fact sufficient in most cases to adequately identify a negative test, or to accurately define the degree of aggressiveness of a lesion, especially if larger or with major characteristics of malignancy. This feature would give the DCE a secondary role, probably limited to a second evaluation of the lesion location, for detecting small cancer or in case of controversy. However, DCE has proved to increase the sensitivity of prostate MRI, though a less specificity. Therefore, an appropriate decision algorithm is needed to standardize the MRI approach. Aim of this review study was to provide a schematic description of bpMRI and mpMRI approaches in the study of prostatic anatomy, focusing on comparative validity and current DCE application. Additional theoretical considerations on prostate MRI are provided.

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

The growing interest in multiparametric MRI is leading to important changes in the diagnostic process of prostate cancer. MRI-targeted biopsy is likely to become a standard for the diagnosis of prostate cancer in the next years. Despite it is well known that MRI has no role as a staging technique, it is clear that multiparametric MRI may be of help in active surveillance protocols. Noteworthy, MRI in active surveillance is not recommended, but a proper understanding of its potential may be of help in achieving the goals of a delayed treatment strategy. Moreover, the development of minimally invasive techniques, like laparoscopic and robotic surgery, has led to greater expectations as regard to the functional outcomes of radical prostatectomy. Multiparametric MRI may play a role in planning surgical strategies, with the aim to provide the highest oncologic outcome with a minimal impact on the quality of life. We maintain that a proper anatomic knowledge of prostate lesions may allow the surgeon to achieve a better result in planning as well as in performing surgery and help the surgeon and the patient engage in a shared decision in planning a more effective strategy for prostate cancer control and treatment. This review highlights the advantages and the limitations of multiparametric MRI in prostate cancer diagnosis, in active surveillance and in planning surgery.

Magnetic resonance imaging of the prostate after focal therapy with high-intensity focused ultrasound

For clinically significant, locally confined prostate cancer, whole-gland radical prostatectomy and radiotherapy are established effective treatment strategies that, however, come at a cost of significant morbidity related to urinary and sexual side effects. The concept of risk stratification paired with a better understanding of prognostic factors has led to the development of alternative management options including active surveillance and focal therapy for appropriately selected patients with localized disease. High-intensity focused ultrasound (HIFU) is one such minimally invasive, image-guided treatment option for prostate cancer. Due to the relative novelty of HIFU and the increased use of magnetic resonance imaging in prostate cancer, many radiologists are not yet familiar with imaging findings related to HIFU, their temporal evolution as well as imaging appearance of recurrent disease after this type of focal therapy. HIFU induces sharply demarcated, localized coagulative necrosis of a tumor through thermal energy delivered via an endorectal or transurethral ultrasound transducer. In this pictorial review, we aim at providing relevant background information that will guide the reader through the general principles of HIFU in the prostate, as well as demonstrate the imaging appearance of expected post-HIFU changes versus recurrent tumor.

Biomechanically constrained non-rigid MR-TRUS prostate registration using deep learning based 3D point cloud matching

A non-rigid MR-TRUS image registration framework is proposed for prostate interventions. The registration framework consists of a convolutional neural networks (CNN) for MR prostate segmentation, a CNN for TRUS prostate segmentation and a point-cloud based network for rapid 3D point cloud matching. Volumetric prostate point clouds were generated from the segmented prostate masks using tetrahedron meshing. The point cloud matching network was trained using deformation field that was generated by finite element analysis. Therefore, the network implicitly models the underlying biomechanical constraint when performing point cloud matching. A total of 50 patients' datasets were used for the network training and testing. Alignment of prostate shapes after registration was evaluated using three metrics including Dice similarity coefficient (DSC), mean surface distance (MSD) and Hausdorff distance (HD). Internal point-to-point registration accuracy was assessed using target registration error (TRE). Jacobian determinant and strain tensors of the predicted deformation field were calculated to analyze the physical fidelity of the deformation field. On average, the mean and standard deviation were 0.94±0.02, 0.90±0.23 mm, 2.96±1.00 mm and 1.57±0.77 mm for DSC, MSD, HD and TRE, respectively. Robustness of our method to point cloud noise was evaluated by adding different levels of noise to the query point clouds. Our results demonstrated that the proposed method could rapidly perform MR-TRUS image registration with good registration accuracy and robustness.

Histotripsy: The Next Generation of High-Intensity Focused Ultrasound for Focal Prostate Cancer Therapy

This article reviews the most current methods and technological aspects of high-intensity focused ultrasound (HIFU), which is termed histotripsy. The rationale for focal therapy for prostate carcinoma rather than prostatectomy, which is being used extensively throughout Europe and Asia, is presented, and an argument for why HIFU is the modality of choice for primary therapy and recurrent disease is offered. The article presents a review of the technical advances including higher ultrasound beam energy than current thermal HIFU which allows for more accurate tissue targeting, less collateral tissue damage, and faster treatment times. Finally, the article presents a discussion about the advantage of ultrasound guidance for histotripsy in preference to magnetic resonance imaging guidance primarily based on cost, ease of application, and portability.

Whole and hemi-gland cryoablation for primary localized prostate cancer: Short and medium-term oncological and functional outcomes

INTRODUCTION

To compare oncological, functional and post-operative outcomes of hemi (HC) vs. whole gland (WGC) cryoablation as first line treatment of localized prostate cancer.

MATERIAL AND METHOD

Sixty-six consecutive patients undertaking whole-gland cryoablation (WGC=40) or hemi-cryoablation (HC=26) in a tertiary referral centre between 2010 and 2018 were included. All patients had a low-intermediate risk prostate cancer according to D'Amico risk classification. Hemi-ablation was proposed in case of biopsy and prostate MRI proven unilateral prostate cancer. Primary endpoint was Cryotherapy Failure for which 3 definitions were considered and compared: 1) biochemical failure (> PSA nadir+≥ 2 ng/mL), 2) positive prostate re-biopsy with Gleason score ≥ 7, 3) initiation of further prostate cancer treatment.

RESULTS

Median patients age at treatment was 74 [42-81] vs. 76 [71-80] years in WGC vs. HC group, respectively (p=.08). Low and intermediate D'Amico risk group were 15% and 85% vs. 23% and 77% (p=.75), respectively. Median follow- up time was 41 [1.5-99.0] vs. 27 [0.9-93] months (p=.03). Four-years cryotherapy failure free survival in WGC vs. HC were 69% vs. 53% with definition 1 (p=.24), 82% vs. 80% with definition 2 (p=.95), 83% vs. 77% with definition 3 (p=.73). Early and 1-year urinary continence were 60% and 83% in WGC vs. 72% and 83% in HC (p=.26). De novo impotency after cryotherapy was 75% vs. 46% (p=.33) in WGC vs. HC.

CONCLUSIONS

In our cohort of highly selected patients with unilateral low/intermediate risk PCa, hemi-cryoablation may provide similar oncological outcomes and less early complications compared to whole-gland cryoablation.

Contemporary treatments in prostate cancer focal therapy

PURPOSE OF REVIEW

Radical treatments for prostate cancer are associated with significant morbidity, including incontinence and erectile dysfunction. Advances in the field of prostate MRI and desire to reduce treatment morbidities have led to a rapid growth in focal treatments for prostate cancer. Here, we review novel focal prostate cancer treatments and their associated recent clinical data, with a particular focus on data reported within the last 24 months.

RECENT FINDINGS

High-intensity focal ultrasound, focal laser ablation, irreversible electroporation, focal cryotherapy, and photodynamic therapy have been used as treatment modalities for localized prostate cancer treatment. Despite the great variety of treatment techniques, each of these modalities is characterized by a significant rate of prostate cancer persistence within treatment zones (6-50%) and the presence of residual cancer within the prostate on rebiopsy (24-49%). These treatments, however, are associated with very low rates of high-grade complications, rare incontinence, and only mild or transient reductions in erectile function. The most common adverse events are urinary tract infections, hematuria, and urinary retention.

SUMMARY

Prostate cancer focal therapy is an attractive option for well-selected patients because of its low complication profile; however, long-term oncologic outcome is still lacking and early recurrence rates are high, limiting the ability of most urologic associations from endorsing its routine use.