Trans-rectal Ultrasound-Guided Autologous Blood Injection in the Interprostatorectal Space Prior to Percutaneous MRI-Guided Cryoablation of the Prostate

MRI-Guided Salvage Focal Cryoablation: A 10-Year Single-Center Experience in 114 Patients with Localized Recurrent Prostate Cancer

Patients with localized recurrent prostate cancer (PCa) are eligible for androgen-deprivation therapy, salvage radical prostatectomy (RP) or radiation therapy. These treatments are associated with serious side-effects, illustrating the need for alternative local treatment options with lower morbidity rates. All patients who underwent magnetic resonance imaging (MRI)-guided salvage focal cryoablation (SFC) with localized recurrent PCa between 2011-2021 (n = 114) were included. Two subgroups were formed: patients without (n = 99) and with prior RP (n = 15). We assessed the recurrence- (RFS) and treatment-free survival (TFS), measured from date of treatment to date of recurrence or initiation of additional salvage treatment, using Kaplan-Meier plots. Complications were reported using the Clavien-Dindo (CD) scale. Overall 1-year and 5-year RFS were 76.0% and 25.1%, and overall 1-year and 5-year TFS were 91.5% and 58.2%, respectively. Patients without prior RP showed a significantly higher 1-year (78.5% vs. 52.5%) and 5-year RFS (28.1% vs. 0.0%; p = 0.03), and a trend towards a higher 1-year (92.6% vs. 79.0%) and 5-year TFS (60.2% vs. 23.0%; p = 0.10) compared to those with prior RP. A total of 46 complications occurred in 37 patients, and the overall complication rate was 32.4% (37/114 patients). The majority (41/46; 89.1%) of complications were minor (CD 1-2). Overall (31.3 vs. 40.0%) and major (3.0 vs. 13.3%) complication rates were lower in patients without compared to those with prior RP, respectively. MRI-guided SFC is an effective and safe therapy for patients with recurrent PCa, and has proved to delay and potentially prevent the initiation of salvage treatments. Patients with locally recurrent PCa after prior RP had an increased risk of recurrence, a shortened time to additional treatment, and more complications compared to those without prior RP, which should be considered when selecting patients for SFC.

MR Imaging in Real Time Guiding of Therapies in Prostate Cancer

Magnetic resonance imaging (MRI)-guided therapy for prostate cancer (PCa) aims to reduce the treatment-associated comorbidity of existing radical treatment, including radical prostatectomy and radiotherapy. Although active surveillance has been used as a conservative method to reduce overtreatment, there is a growing demand for less morbidity and personalized (focal) treatment. The development of multiparametric MRI was of real importance in improving the detection, localization and staging of PCa. Moreover, MRI has been useful for lesion targeting within the prostate, as it is used in the guidance of prostate biopsies, by means of cognitive registration, MRI-ultrasound fusion guidance or direct in-bore MRI-guidance. With regard to PCa therapies, MRI is used for precise probe placement into the lesion and to accurately monitor the treatment in real-time. Moreover, advances in MR-compatible thermal ablation allow for noninvasive real-time temperature mapping during treatment. In this review, we present an overview of the current status of MRI-guided therapies in PCa, focusing on cryoablation, focal laser ablation, high intensity focused ultrasound and transurethral ultrasound ablation. We explain the important role of MRI in the evaluation of the completeness of the ablation and during follow-up. Finally, we will discuss the challenges and future development inherent to these new technologies.

Rectal wall saline displacement for improved margin during MRI-guided cryoablation of primary and recurrent prostate cancer

PURPOSE

To describe safety, efficacy, and added oncologic margin of saline displacement of the rectal wall during MRI-guided cryoablation of primary and recurrent prostate cancer.

METHODS

A retrospective review was conducted for patients who underwent MRI-guided cryoablation with saline displacement of the rectal wall for treatment of primary and recurrent prostate cancer over a 2-year period. Saline displacement was used when the distance from the edge of the ablation area to the rectal wall was insufficient to provide at least a 5-mm treatment margin. Pre- and post-ablation rectal wall displacement distances as well as ablative zone margins were assessed with MRI. Saline displacement distance was measured from the rectal wall to the edge of the lesion for focal lesion ablation and from the edge of the prostate for hemi-gland ablation. Immediate and intermediate-term complications were assessed.

RESULTS

Saline displacement was used in 25 patients undergoing MRI-guided cryoablation. Twenty-one patients underwent salvage cryoablation, while four patients had it as primary treatment for prostate cancer. Median pre- and post- saline displacement rectal wall displacement distances were 6.0 and 11.2 mm, respectively (P < 0.0001). Median-added oncologic margin achieved by saline displacement was 4.6 mm (range 0.6-26.5). Median follow-up was 14 months (range 5-29). There were no intra-procedural complications and 3 patients experienced minor (Clavien-Dindo grade I) complications. One rectal complication occurred in a patient undergoing salvage cryotherapy with a history of extensive pelvic surgery and radiation.

CONCLUSIONS

Saline infusion at the time of MRI- guided cryoablation for prostate cancer resulted in increased distances between the target lesion and rectum. This is a useful technique in providing an added oncologic margin when treating lesions close to the rectal wall.

Percutaneous MR-guided prostate cancer cryoablation technical updates and literature review

Prostate cancer (PCa) is the most common malignant tumor in males. The benefits in terms of overall reduction in specific mortality due to the widespread use of Prostate Specific Antigen (PSA) screening and the advancements in the curative treatments (radical prostatectomy or radiotherapy) appear to have reached a plateau. There remains, however, the questions of overdiagnosis and overtreatment of such patients. Currently, the main challenge in the treatment of patients with clinically organ-confined PCa is to offer an oncologically efficient treatment with as little morbidity as possible. Amongst the arising novel curative techniques for PCa, cryoablation (CA) is the most established one, which is also included in the NICE and AUA guidelines. CA is commonly performed under ultrasound guidance with the inherent limitations associated with this technique. The recent advancements in MRI have significantly improved the accuracy of detecting and characterizing a clinically significant PCa. This, alongside the development of wide bore interventional MR scanners, has opened the pathway for in bore PCa treatment. Under MRI guidance, PCa CA can be used either as a standard whole gland treatment or as a tumor targeted one. With MR-fluoroscopy, needle guidance capability, multiplanar and real-time visualization of the iceball, MRI eliminates the inherent limitations of ultrasound guidance and can potentially lead to a lower rate of local complications. The aim of this review article is to provide an overview about PCa CA with a more specific insight on MR guided PCa CA; the limitations, challenges and applications of this novel technique will be discussed.

Establishing MRI-guided prostate intervention at a UK Centre

OBJECTIVES

To describe our preliminary experience in establishing an MRI suite capable to deliver targeted prostate biopsy and cryoablation.

METHODS

This article includes a description of the necessary infrastructure alterations, scanning sequence suggestions, anaesthetic advice, and practical procedural considerations. We aim to examine the anticipated issues most UK centres would encounter and offer our experience in overcoming them. During this process we will also explore some of the technical aspects of MRI-guided prostate biopsy and cryoablation.

RESULTS

The clinical indication, treatment rationale, intervention strategy, and initial clinical outcomes are described for our first series of patients.

CONCLUSION

MRI-guided prostate intervention provides many theoretical advantages over traditional TRUS guidance. This article demonstrates some of the complexities encountered in establishing this technique in a UK centre, and the proposed solutions.

ADVANCES IN KNOWLEDGE

This article gives an account of establishing the first MRI intervention suite in the UK. It demonstrates some of the logistical considerations, and offers the unit's early experience.

Percutaneous MR-guided whole-gland prostate cancer cryoablation: safety considerations and oncologic results in 30 consecutive patients

OBJECTIVE

To assess the safety and oncological efficacy of percutaneous MR-guided whole-gland prostate cancer (PCa) cryoablation (CA).

METHODS AND MATERIALS

Between July 2009 and January 2018, 30 patients (mean age 72.9 ± 5.13 years) with histologically proven, organ-confined (≤ T2cN0M0), predominantly low/intermediate-risk PCa (median Gleason score 7; mean prostate specific antigen 6.05 ± 3.74 ng ml^-1 ) underwent MR-guided whole-gland CA. Patients were selected on the basis of prior pelvic radiotherapy (n = 16; 12 for previous PCa), or contra indication/refusal of surgery or radiotherapy. Complications, local progression-free survival (LPFS) and overall survival (OS) were retrospectively investigated.

RESULTS

Eighteen [60%] patients reported procedure-related complications: 5/18 [28%] needed surgical/interventional treatments and 13 [72%] conservative or pharmacological treatment. Eleven [73%] complications were noted in the first 15 patients and 7 [47%] in the last 15 patients (p = 0.26). Mean nadir prostate specific antigen was 0.24 ± 1.5 ng ml^-1 (mean follow-up 3.8 years; range: 2 - 2915 days). Seven [23%] patients developed histologically proven local progression (mean time to recurrence 775 days, range: 172 - 2014). Mean clinical follow-up was 3.8 years (range 1-2915 days). LPFS was 92.0, 75.7 and 69.4 % at 1-, 3- and 5 year follow-up, respectively. For patients in salvage treatment, LPFS was 100%, 75%, and 75% at 1-, 3- and 5 year follow-up. OS was 100%, 94.4 and 88.5 % at 1-, 3- and 5 year follow-up respectively, with no patients dying from PCa.

CONCLUSION

Whole-gland PCa CA offers good oncological efficacy, particularly in post-radiotherapy cases. Although the complication rate is significant, the majority is minor and is managed with conservative or pharmacologic management.

ADVANCES IN KNOWLEDGE

MRI-guided whole-gland prostate cancer cryoablation offers good oncological efficacy, particularly in post-radiotherapy cases with a contained complication rate.