Prostate cancer therapy with high-intensity focused ultrasound

Management of the Devastated Bladder Outlet after Prostate CANCER Treatment

PURPOSE OF REVIEW

Devastating complications of the bladder outlet resulting from prostate cancer treatments are relatively uncommon. However, the combination of the high incidence of prostate cancer and patient longevity after treatment have raised awareness of adverse outcomes deteriorating patients' quality of life. This narrative review discusses the diagnostic work-up and management options for bladder outlet obstruction resulting from prostate cancer treatments, including those that require urinary diversion.

RECENT FINDINGS

The devastated bladder outlet can be a consequence of the treatment of benign conditions, but more frequently from complications of pelvic cancer treatments. Regardless of etiology, the initial treatment ladder involves endoluminal options such as dilation and direct vision internal urethrotomy, with or without intralesional injection of anti-fibrotic agents. If these conservative strategies fail, surgical reconstruction should be considered. Although surgical reconstruction provides the best prospect of durable success, reconstructive procedures are also associated with serious complications. In the worst circumstances, such as prior radiotherapy, failed reconstruction, devastated bladder outlet with end-stage bladders, or patient's severe comorbidities, reconstruction may neither be realistic nor justified. Urinary diversion with or without cystectomy may be the best option for these patients. Thorough patient counseling before treatment selection is of utmost importance. Outcomes and repercussions on quality of life vary extensively with management options. Meticulous preoperative diagnostic evaluation is paramount in selecting the right treatment strategy for each individual patient. The risk of bladder outlet obstruction, and its severest form, devastated bladder outlet, after treatment of prostate cancer is not negligible, especially following radiation. Management includes endoluminal treatment, open or robot-assisted laparoscopic reconstruction, and urinary diversion in the worst circumstances, with varying success rates.

Image-Guided Prostate Cryoablation: State-of-the-Art

Image-guided focal therapy has increased in popularity as a treatment option for patients with primary and locally recurrent prostate cancer. This review will cover the basic indications, evaluation, treatment algorithm, and follow-up for patients undergoing image-guided ablation of the prostate. Additionally, this paper will serve as an overview of some technical approaches to cases so that physicians can familiarize themselves with working in this space. While the focus of this paper is prostate cryoablation, readers will obtain a basic literature overview of some of the additional available image-guided treatment modalities for focal prostate therapy.

High-intensity focused ultrasound for the treatment of prostate cancer: assessing location of failure after focal therapy in prostate cancer and review of histological characteristics and clinicopathologic correlates after treatment-a 5-year experience

High-intensity focused ultrasound (HIFU) is a noninvasive treatment option used for localized prostate cancer or salvage surgery after failed radiation therapy. Histological changes in post-treatment needle biopsies are reviewed to better understand HIFU failures. Between 2016 and 2021, 50 patients with localized prostate cancer were enrolled and treated in this study. Of these, 10 patients underwent salvage therapy after radiation failure and 7 did not have post-treatment needle biopsies available for review and were excluded. Inclusion criteria included pathologically confirmed prostate cancer and clinical stage T1/T2 disease. We describe the histological changes in post-treatment needle biopsies as part of routine follow-up. Biopsies were examined for presence, distribution and extent of residual adenocarcinoma, Gleason score, and ablative tissue changes. A total of 33 patients underwent HIFU hemi-ablation treatment of localized prostate cancer as primary treatment with post-treatment biopsies available for review. The average mean age of the patients was 64 years (range, 52-81 years). The average PSA (prostate-specific antigen) level of the patients was 6.3 ng/mL (range, 2.4-14.7 ng/mL). The Gleason scores assigned in pretreatment prostate needle biopsies are as follows: 3 + 3 (1 case, 3%), 3 + 4 (21 cases, 64%), 4 + 3 (9 cases, 27%), and 4 + 4 (2 cases, 6%). In post-treatment needle biopsies, 33 cases (100%) showed variable degrees of fibrosis ranging from mild to moderate. Twenty-four of 33 cases (73%) showed necrosis usually associated with acute and/or chronic inflammation. Histological examination of benign glands revealed glandular heterogeneity including atrophy and basal cell hyperplasia. Eight cases (24%) had residual prostatic adenocarcinoma after treatment, of which 4 cases were assigned Gleason score: ≥3 + 4. In cases with residual adenocarcinoma, 8 cases (100%) showed nuclear enlargement, 5 cases (63%), cytoplasmic vacuolization, and 1 case (13%) showed nuclear pyknosis; otherwise, no discernible effects of treatment were seen. Morphological alterations included a spectrum of changes ranging from extensive coagulative stromal necrosis secondary to thermal injury to atrophic changes in benign prostatic tissue after HIFU treatment. Our findings also support the hypothesis that HIFU failure results from inadequate targeting rather than failure within a treated zone.

Evolution of Focal Therapy in Prostate Cancer: Past, Present, and Future

Organ sparing approaches for the management of localized prostate cancer were developed in part to overcome the morbidity associated with standard, whole gland treatment options. The first description of focal therapy was now over two decades ago and since that time much has changed. The evolution of patient selection, the approach to ablation, and surveillance after focal therapy have mirrored the technologic advancements in the field as well as the improved understanding of the biology of low-grade, low-risk prostate cancer. This review presents the evidence for the basis of focal therapy from the past to the present and future endeavors.

Devastated Bladder Outlet in Pelvic Cancer Survivors: Issues on Surgical Reconstruction and Quality of Life

Bladder outlet obstruction following treatment of pelvic cancer, predominantly prostate cancer, occurs in 1-8% of patients. The high incidence of prostate cancer combined with the long-life expectancy after treatment has increased concerns with cancer survivorship care. However, despite increased oncological cure rates, these adverse events do occur, compromising patients' quality of life. Non-traumatic obstruction of the posterior urethra and bladder neck include membranous and prostatic urethral stenosis and bladder neck stenosis (also known as contracture). The devastated bladder outlet can result from benign conditions, such as neurogenic dysfunction, trauma, iatrogenic causes, or more frequently from complications of oncologic treatment, such as prostate, bladder and rectum. Most posterior urethral stenoses may respond to endoluminal treatments such as dilatation, direct vision internal urethrotomy, and occasionally urethral stents. Although surgical reconstruction offers the best chance of durable success, these reconstructive options are fraught with severe complications and, therefore, are far from being ideal. In patients with prior RT, failed reconstruction, densely fibrotic and/or necrotic and calcified posterior urethra, refractory incontinence or severe comorbidities, reconstruction may not be either feasible or recommended. In these cases, urinary diversion with or without cystectomy is usually required. This review aims to discuss the diagnostic evaluation and treatment options for patients with bladder outlet obstruction with a special emphasis on patients unsuitable for reconstruction of the posterior urethra and requiring urinary diversion.

High-Intensity Focused Ultrasound: Current Status for Image-Guided Therapy

Image-guided high-intensity focused ultrasound (HIFU) is an innovative therapeutic technology, permitting extracorporeal or endocavitary delivery of targeted thermal ablation while minimizing injury to the surrounding structures. While ultrasound-guided HIFU was the original image-guided system, MR-guided HIFU has many inherent advantages, including superior depiction of anatomic detail and superb real-time thermometry during thermoablation sessions, and it has recently demonstrated promising results in the treatment of both benign and malignant tumors. HIFU has been employed in the management of prostate cancer, hepatocellular carcinoma, uterine leiomyomas, and breast tumors, and has been associated with success in limited studies for palliative pain management in pancreatic cancer and bone tumors. Nonthermal HIFU bioeffects, including immune system modulation and targeted drug/gene therapy, are currently being explored in the preclinical realm, with an emphasis on leveraging these therapeutic effects in the care of the oncology patient. Although still in its early stages, the wide spectrum of therapeutic capabilities of HIFU offers great potential in the field of image-guided oncologic therapy.

High-intensity focused ultrasound: advances in technology and experimental trials support enhanced utility of focused ultrasound surgery in oncology

High-intensity focused ultrasound (HIFU) is a rapidly maturing technology with diverse clinical applications. In the field of oncology, the use of HIFU to non-invasively cause tissue necrosis in a defined target, a technique known as focused ultrasound surgery (FUS), has considerable potential for tumour ablation. In this article, we outline the development and underlying principles of HIFU, overview the limitations and commercially available equipment for FUS, then summarise some of the recent technological advances and experimental clinical trials that we predict will have a positive impact on extending the role of FUS in cancer therapy.

Respiration-induced movement correlation for synchronous noninvasive renal cancer surgery

Noninvasive surgery (NIS), such as high-intensity focused ultrasound (HIFU)-based ablation or radiosurgery, is used for treating tumors and cancers in various parts of the body. The soft tissue targets (usually organs) deform and move as a result of physiological processes such as respiration. Moreover, other deformations induced during surgery by changes in patient position, changes in physical properties caused by repeated exposures and uncertainties resulting from cavitation also occur. In this paper, we present a correlation-based movement prediction technique to address respiration-induced movement of the urological organs while targeting through extracorporeal trans-abdominal route access. Among other organs, kidneys are worst affected during respiratory cycles, with significant three-dimensional displacements observed on the order of 20 mm. Remote access to renal targets such as renal carcinomas and cysts during noninvasive surgery, therefore, requires a tightly controlled real-time motion tracking and quantitative estimate for compensation routine to synchronize the energy source(s) for precise energy delivery to the intended regions. The correlation model finds a mapping between the movement patterns of external skin markers placed on the abdominal access window and the internal movement of the targeted kidney. The coarse estimate of position is then fine-tuned using the Adaptive Neuro-Fuzzy Inference System (ANFIS), thereby achieving a nonlinear mapping. The technical issues involved in this tracking scheme are threefold: the model must have sufficient accuracy in mapping the movement pattern; there must be an image-based tracking scheme to provide the organ position within allowable system latency; and the processing delay resulting from modeling and tracking must be within the achievable prediction horizon to accommodate the latency in the therapeutic delivery system. The concept was tested on ultrasound image sequences collected from 20 healthy volunteers. The results indicate that the modeling technique can be practically integrated into an image-guided noninvasive robotic surgical system with an indicative targeting accuracy of more than 94%. A comparative analysis showed the superiority of this technique over conventional linear mapping and modelfree blind search techniques.

Histopathological findings after treatment of prostate cancer using high-intensity focused ultrasound (HIFU)

BACKGROUND

High-intensity focused ultrasound (HIFU) treatment is a novel minimally invasive therapeutic option for patients with localized prostate cancer. Little is known about the histological findings in prostate biopsies upon HIFU treatment.

METHOD

We examined the spectrum of histological changes in prostate biopsies of 25 prostate cancer patients who were previously treated with HIFU. The biopsies were taken 180 days after HIFU treatment.

RESULTS

Seventy-two percent of the cases showed necrosis, often accompanied by acute, chronic, or granulomatous inflammation. Mild or moderate fibrosis was present in all biopsies. In benign glands, histological examination revealed a heterogeneous cellular damage and cellular response including cytologic atypia and basal cell hyperplasia. Eleven patients (44%) had residual prostatic carcinoma after treatment. In cases with residual adenocarcinoma, the majority of the cases (9/11, 88%) do no have apparent treatment effects. Two cases showed nuclear pyknosis. In summary, we report the histological findings in benign and malignant prostatic tissues after HIFU treatment. These findings include a spectrum of morphological changes ranging from apparent necrosis to more subtle cellular damage can be observed in benign prostatic tissue after HIFU treatment. There were minimal morphologic changes in residual adenocarcinoma after HIFU treatments.

CONCLUSION

The pathologist should be aware of common histologic findings in prostatic biopsies after HIFU treatment. We recommend routine reporting of Gleason scores in post-HIFU needle biopsies.

Prostate cancer detection with 3 T MRI: comparison of diffusion-weighted imaging and dynamic contrast-enhanced MRI in combination with T2-weighted imaging

PURPOSE

To evaluate the diagnostic ability of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced imaging (DCEI) in combination with T2-weighted imaging (T2WI) for the detection of prostate cancer using 3 T magnetic resonance imaging (MRI) with a phased-array body coil.

MATERIALS AND METHODS

Fifty-three patients with elevated serum levels of prostate-specific antigen (PSA) were evaluated by T2WI, DWI, and DCEI prior to needle biopsy. The obtained data from T2WI alone (protocol A), a combination of T2WI and DWI (protocol B), a combination T2WI and DCEI (protocol C), and a combination of T2WI plus DWI and DCEI (protocol D) were subjected to receiver operating characteristic (ROC) curve analysis.

RESULTS

The sensitivity, specificity, accuracy, and area under the ROC curve (Az) for region-based analysis were: 61%, 91%, 84%, and 0.8415, respectively, in protocol A; 76%, 94%, 90%, and 0.8931, respectively, in protocol B; 77%, 93%, 89%, and 0.8655, respectively, in protocol C; and 81%, 96%, 92%, and 0.8968, respectively in protocol D. ROC analysis revealed significant differences between protocols A and B (P = 0.0008) and between protocols A and D (P = 0.0004).

CONCLUSION

In patients with elevated PSA levels the combination of T2WI, DWI, DCEI using 3 T MRI may be a reasonable approach for the detection of prostate cancer.

Utility of racemase and other immunomarkers in the detection of adenocarcinoma in prostatic tissue damaged by high intensity focused ultrasound therapy

AIMS

High intensity focused ultrasound (HIFU) is an emerging alternative for the treatment of prostate adenocarcinoma. Alpha-methylacyl-CoA racemase (AMACR) has been shown to be a sensitive immunomarker for prostate cancer, however, there is no information available concerning its utility and that of other immunomarkers for the detection of malignancy after HIFU therapy.

METHODS

AMACR expression was examined in 11 cases of prostatic carcinoma treated by HIFU, with histological evidence of residual carcinoma. In seven cases tumour was examined from thin core biopsies and in four cases from tissue fragments obtained by transurethral resection of prostate (TURP). In addition to AMACR, immunostaining was also undertaken for p63, cytokeratin 34betaE12, cytokeratin 5, cytokeratin 8-18, prostate specific alkaline phosphatase (PSAP), prostate specific antigen (PSA), chromogranin and CD56.

RESULTS

In two of the cases foci of tumour were cut out in serial sections. AMACR was expressed in eight of nine evaluable cases (4/5 biopsies and 4/4 TURP specimens). Cytokeratin 8-18 and PSAP were positive in all cases, whereas PSA was positive in five of nine cases. Cytokeratin 34betaE12, cytokeratin 5, and p63 marked the basal layer in normal prostatic glands, but were negative in neoplastic glands. In four cases we found tumour cells with positive staining for CD56 and chromogranin.

CONCLUSIONS

A panel with positive markers for AMACR, and negative markers for p63/cytokeratin 5/cytokeratin 34betaE12 confirms the neoplastic nature of the residual glands on biopsies or TURP fragments sampled after HIFU therapy.

Efficacy of laser-activated gold nanoshells in ablating prostate cancer cells in vitro

BACKGROUND AND PURPOSE

Nanoshells (NS) are nanoparticles consisting of a dielectric silica core covered by a thin gold shell. Nanoshells can be designed to absorb near-infrared (NIR) light strongly to generate heat and provide optically guided hyperthermic ablation. Laser-activated gold nanoshells (LAGN) may offer a minimally invasive targeted ablative treatment for prostate cancer. We studied the in-vitro effectiveness of LAGN ablation on human prostate cancer cells.

MATERIALS AND METHODS

Two human prostate cancer (PCa) cell lines, PC-3 and C4-2, were grown to 80% confluency in T medium with 5% fetal bovine serum. In order to determine a threshold concentration of gold nanoshells (GNS) needed to achieve full cellular ablation, dose titration was performed. In subsequent experiments, GNS were added to PCa cells in phosphate-buffered saline at concentrations above the predetermined threshold. The cells were then exposed to NIR light (810 nm, 88 W/cm2) for 5 minutes and stained immediately for viability using the Calcein AM assay. For determining long-term cell survival, the crystal violet assay was employed.

RESULTS

The GNS could be evenly distributed across the culture plates. A ratio of 5000 GNS per PCa cell was critical for achieving cell kill. Cells treated with GNS + NIR demonstrated a laser-specific zone of cell death. The crystal violet viability assay confirmed consistent cell death rather than induction of cell dormancy. Cells treated with GNS alone or with NIR light alone demonstrated no toxicity.

CONCLUSION

Laser-activated gold nanoshells can ablate human PCa cells in vitro. This nanoparticle technology is an attractive therapeutic agent for selective tumor ablation.

Diffusion-Weighted Imaging of the Prostate at 3 T for Differentiation of Malignant and Benign Tissue in Transition and Peripheral Zones

OBJECTIVE

To evaluate prospectively the use of apparent diffusion coefficients (ADCs) for the differentiation of malignant and benign tissue in the transition (TZ) and peripheral (PZ) zones of the prostate diffusion-weighted imaging (DWI) at 3 T magnetic resonance imaging (MRI) using a phased-array coil.

METHODS

The DWI at 3-T MRI was performed on a total of 35 patients before radical prostatectomy. A single-shot echo-planar imaging DWI technique with b = 0 and b = 1000 s/mm2 was used. The ADC values were measured in both benign and malignant tissues in the PZ and TZ using regions of interest. Differences between PZ and TZ ADC values were estimated using a paired Student t test. Presumed ADC cutoff values in the PZ and TZ for the diagnosis of cancer were assessed by receiver operating characteristic analysis.

RESULTS

The ADC values of malignant tissues were significantly lower than those of benign tissues in the PZ and TZ (P < 0.001; 1.32 +/- 0.24 x 10(-3) mm2/s vs 1.97 +/- 0.25 x 10(-3) mm2/s, and 1.37 +/- 0.29 x 10(-3) mm2/s vs 1.79 +/- 0.19 x 10(-3) mm2/s, respectively). For tumor diagnosis, cutoff values of 1.67 x 10(-3) mm2/s (PZ) and 1.61 x 10(-3) mm2/s (TZ) resulted in sensitivities and specificities of 94% and 91% and 90% and 84%, respectively.

CONCLUSIONS

The DWI of the prostate at 3T MRI using a phased-array coil was useful for the differentiation of malignant and benign tissues in the TZ and PZ.