Focal therapy in the management of prostate cancer: an emerging approach for localized prostate cancer

Advances in localized prostate cancer: A special focus on photothermal therapy

Prostate cancer (PCa) is a high prevalence disease, per 10000 habitants, that tends to increase with age. This pathology is difficult to detect at an early stage due to the absence of symptoms, hence the importance of monitoring signs for early detection. This disease can be detected by various methods, including plasmatic levels of prostate-specific antigen (PSA) and rectal touch, with biopsy being necessary to confirm the diagnosis. Patients affected by prostate cancer can have localized or advanced disease. There are conventional approaches that have been used as a reference in localized cancer, such as active surveillance, surgery, or radiotherapy. However, the adverse effects might vary and, sometimes, they can be permanent. An overview about the innovative therapeutic approaches to improve outcomes in terms of both tumor remission and side effects for localized PCa is presented. In case of emerging light-based treatment strategies, they aimed at ablating tumor tissue by inducing an external light are non-invasive, localized and, considerably, they are able to reduce lesions in peripheral tissues. One is photodynamic therapy (PDT) and it involves the photooxidation of molecules culminating in the formation of reactive oxygen species (ROS), inducing cell death. On the other hand, photothermal therapy (PTT) is based on inducing hyperthermia in cancer cells by irradiating them with beams of light at a specific wavelength. To improve the heat generated, gold nanoparticles (AuNPs) have those desirable characteristics that have drawn attention to PTT. Various studies point to AuNPs as efficient nanomaterials in PTT for the treatment of tumors, including prostate cancer. This review includes the most representative advances in this research field, dated from 1998 to 2023. It is noticed that several advances have been made and the way to find the effective treatment without impacting adverse side effects is shorter.

MR Imaging-Guided Prostate Cancer Therapies

Prostate cancer is the most common malignancy diagnosed in men. MR imaging-guided therapies for prostate cancer have become an increasingly common treatment alternative to traditional whole-gland therapies, such as radical prostatectomy or radiation therapy. This is especially true in men with localized, low- to intermediate-risk prostate cancer. Although long-term oncologic data remain limited, the authors describe several MR imaging-guided therapeutic options for the treatment of prostate cancer, including cryoablation, laser ablation, transrectal high-intensity focused ultrasound, and transurethral ultrasound ablation.

Clinical application of the therapeutic ultrasound in urologic disease: Part II of the therapeutic ultrasound in urology

This article aimed to review the clinical application and evidence of the therapeutic ultrasound in detail for urological diseases such as prostate cancer, kidney tumor, erectile dysfunction, and urolithiasis. We searched for articles about high-intensity focused ultrasound (HIFU), extracorporeal shock wave therapy, ultrasound lithotripsy, and extracorporeal shockwave lithotripsy (ESWL) in the MEDLINE and Embase. HIFU may be indicated as a primary treatment for low- or intermediate-risk prostate cancer, and salvage therapy for local recurrence as a promising way to address the limitations of current standard therapies. The application of HIFU in treating kidney tumors has scarcely been reported with unsatisfactory results. Evidence indicates that low-intensity shockwave therapy improves subjective and objective erectile function in patients with erectile dysfunction. Regarding the application of ultrasound in stone management, the novel combination of ultrasound lithotripsy and other energy sources in a single probe promises to be a game-changer in efficiently disintegrating large kidney stones in percutaneous nephrolithotomy. ESWL is losing its role in managing upper urinary tract calculi worldwide. The burst-wave lithotripsy and ultrasound propulsion could be the new hope to regain its position in the lithotripsy field. According to our investigations and reviews, cavitation bubbles of the therapeutic ultrasound are actively being used in the field of urology. Although clinical evidence has been accumulated in urological diseases such as prostate cancer, kidney tumor, erectile dysfunction, and lithotripsy, further development is needed to be a game-changer in treating these diseases.

Magnetic resonance image-guided focused ultrasound robotic system for transrectal prostate cancer therapy

BACKGROUND

A magnetic resonance image (MRI) guided robotic device for focussed ultrasound therapy of prostate cancer (PC) was developed. The device offers movement in 5 degrees of freedom (DOF) and uses a single-element transducer that operates at 3.2 MHz, has a diameter of 25 mm and focuses at 45 mm.

METHODS

The MRI compatibility of the system was evaluated in a 1.5 T scanner. The ability of the transducer to create lesions was evaluated in laboratory and MRI settings, on ex vivo pork tissue and in vivo rabbit thigh tissue.

RESULTS

Cavitational and thermal lesions were created on the excised pork tissue. In vivo experiments proved the efficacy of the system in ablating muscle tissue without damaging intervening areas.

CONCLUSIONS

The MRI compatible robotic system can be placed on the table of any commercial MRI scanner up to 7 T. The device has the ability of future use for transrectal focal therapy of PC with the patient in supine position.

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.

Effects of Focal vs Total Cryotherapy and Minimum Tumor Temperature on Patient-reported Quality of Life Compared With Active Surveillance in Patients With Prostate Cancer

OBJECTIVE

To investigate the effects of focal (hemiablation) or total cryotherapy and minimum tumor temperature on patient-reported quality of life (QoL) in patients with prostate cancer.

METHODS

An Institutional Review Board-approved database was reviewed for patients who underwent cryotherapy or active surveillance (AS). QoL questionnaire responses were collected and scores were analyzed for differences between focal and total cryotherapy and between very cold (<-76°C) and moderate-cold (≥-76°C) minimum tumor temperatures.

RESULTS

A total of 197 patients responded to a total of 547 questionnaires. Focal and total cryotherapy patients had initially lower sexual function scores relative to AS (year 1 mean difference focal: -31.7, P <.001; total: -48.1, P <.001). Focal cryotherapy was associated with a more rapid improvement in sexual function. Both focal and total cryotherapy sexual function scores were not statistically significantly different from the AS cohort by postprocedural year 4. Very cold and moderate-cold temperatures led to initially lower sexual function scores relative to AS (year 1 very cold: -38.1, P <.001; moderate-cold: -30.7, P <.001). Moderate-cold temperature scores improved more rapidly than those of very cold temperature. Neither very cold nor moderate-cold temperatures had a statistically significant difference in sexual function scores relative to AS by postprocedural year 4. Urinary function and bowel habits were not significantly different between focal and total cryotherapy and between very cold and moderate-cold temperature groups.

CONCLUSION

Focal cryotherapy and moderate-cold (≥-76°C) temperature were associated with favorable sexual function relative to total cryotherapy and very cold temperature, respectively. No significant differences in urinary function or bowel habits were observed between groups.

Emerging minimally invasive procedures for focal treatment of organ-confined prostate cancer

Prostate cancer is the most common malignancy amongst American men. However, the majority of prostate cancer diagnoses are of low risk, organ-confined disease. Many men elect to undergo definitive treatment, but may benefit from focal therapy to maintain continence and potency. This review reports the mechanism of action and outcomes of emerging focal therapies for prostate cancer. We report the mechanism of action of focal cryotherapy, high intensity focused ultrasound, focal laser ablation, and irreversible electroporation. In addition, we reviewed the largest studies available reporting rates of urinary incontinence, erectile dysfunction, biochemical recurrence-free survival (ASTRO), and post-operative adverse events for each procedure. Each treatment modality stated has a unique mechanism in the ablation of cancerous cells. Genito-urinary symptoms following these studies report incontinence and erectile dysfunction rates ranging from 0-15% and 0-53%, respectively. Biochemical disease-free survival was reported using the ASTRO definition. Some treatment modalities lack the necessary follow-up to determine effectiveness in cancer control. No focal therapy studies reported serious adverse events. These minimally invasive procedures are feasible in a clinical setting and show promising functional and disease control results with short to medium-term follow-up. However, each treatment requires additional robust prospective studies as well as its own unique domain to determine biochemical recurrence free survival to properly determine their role in treatment of organ-confined prostate cancer.

Cryosurgery would be An Effective Option for Clinically Localized Prostate Cancer: A Meta-analysis and Systematic Review

Cryosurgery (CS) has been used on patients with clinically localized PCa for more than 10 years. However, clinical studies evaluating its effectiveness and safety have reported conflicting results. This systematic assessment was performed to obtain comprehensive evidence regarding the potential benefits and safety of CS compared with those of radiotherapy (RT) and radical prostatectomy (RP), respectively. All controlled trials comparing CS with RT or RP and single-arm studies reporting results of CS therapy were identified through comprehensive searches of PubMed, the Cochrane Library and Embase. Ten publications from seven trials, with totally 1252 patients, were included in the meta-analysis, which revealed no significant differences in comparisons of CS vs RT and CS vs RP for overall survival and disease specific survival. However, a significantly lower disease-free survival could be observed for CS than RP. Moreover, a systematic review of literature focusing on comparative data of databases and materials of single-arm trials revealed satisfactory survival results in both primary and salvage CS. Our results showed that cryosurgery would be a relatively effective method for clinically localized prostate cancer with survival results comparable to radiotherapy and radical prostatectomy. However, the large percentage of complications caused by cryosurgery should be carefully monitored.

Treatment of localized prostate cancer using WST-09 and WST-11 mediated vascular targeted photodynamic therapy-A review

BACKGROUND

Photodynamic therapy (PDT) is well known for its direct cytotoxicity of the free radical-producing photochemical reaction, indirect mechanisms of action including modulation of intrinsic anti-tumour immune activity, and occlusion of pathologically altered tumour vessels leading to tumour ischaemia. The aim of this work is to critically review the evidence base for the use of vascular targeted PDT (VTP) to treat low-risk prostate cancer, and to discuss perspectives and challenges yet to be overcome. A brief general overview of focal prostate cancer therapy was provided, followed by a discussion of both basic and clinical research pertaining to prostate cancer VTP, with a focus on the palladium-based WST-09 and WST-11 photosensitisers.

MATERIALS AND METHOD

Literature on VTP for prostate cancer with the fallowing medical subject headings search terms: prostate cancer, photodynamic therapy, vascular targeted photodynamic therapy, bacteriopheophorbide were reviewed. The articles were selected by their relevance to the topic.

RESULTS

The clinical and basic research data available to date show much promise for WST-09, and WST-11 based VTP eventually joining the standard urologist's armamentarium against prostate cancer. With good reported tolerability and efficacy VTP can be proposed as an intermediate treatment for local low risk disease, halfway between watchful waiting and radical therapy.

TOOKAD® Soluble focal therapy: pooled analysis of three phase II studies assessing the minimally invasive ablation of localized prostate cancer

PURPOSE

To evaluate the 6-month effects of the recommended drug and light dosage in focal vascular-targeted photodynamic therapy (VTP) using TOOKAD(®) Soluble in patients with localized prostate cancer (LPCa).

METHODS

We performed a pooled analysis of 117 men with LPCa, PSA <10 ng/mL, and Gleason score ≤ 7 (3 + 4), from 3 studies who received a 10-min intravenous infusion of a single dose of 4 mg/kg TOOKAD(®) Soluble, activated by a 753-nm light at 200 J/cm delivered in the prostate by transperineal fibres under transrectal ultrasound guidance. Primary endpoint was 6-month negative biopsies in the treated lobe(s). PSA was measured at month 1, 3, and 6. Magnetic resonance imaging was performed at day 7, month 3, and 6. International Prostate Symptom Score (IPSS), International Index of Erectile Function (IIEF-5) and adverse events were reported at day 7, month 1, 3, and 6.

RESULTS

Month 6 negative biopsy rate was 68.4 % in the overall evaluable population (N = 114) and 80.6 % for patients treated by hemiablation with light density index (LDI) ≥ 1 (N = 67). Mean prostate necroses at week-1 were 76.5 and 86.3 %, respectively. In both groups, PSA levels at month 6 decreased by 2.0 ng/mL. Small changes from baseline for IPSS and IIEF-5 indicated a slight improvement in urinary function and a slight deterioration in sexual function.

CONCLUSIONS

Focal VTP treatment with TOOKAD(®) Soluble at 4 mg/kg and 200 J/cm resulted in a negative 6-month biopsy rate of 68.4 % for the whole population and 80.6 % for patients treated by hemiablation with LDI ≥ 1. The treatment was well tolerated. Two phase III studies will reach completion in early 2015.

Prostate perfusion mapped by technetium-99m macroaggregated albumin after selective arterial injection

PURPOSE

To determine if perfusion of the prostate can be mapped using technetium-99m ((99m)Tc) macroaggregated albumin (MAA) after selective prostate artery catheterization.

MATERIALS AND METHODS

Selective prostate artery injections of MAA were performed and analyzed in 14 patients; 9 patients received unilateral injection, and 5 patients received bilateral injections (37 MBq/1 mCi per injection). Fused single-photon emission computed tomography/computed tomography (SPECT/CT) images were subsequently acquired using a fiducial marker technique. Perfusion distribution was assessed, and relative intraprostatic versus extraprostatic activity was quantified and compared between groups.

RESULTS

The percentage of the prostate gland containing activity was significantly greater for the bilateral injection group compared with the unilateral injection group (76.6% vs 44.3%, P < .05). The percentage of relative intraprostatic versus extraprostatic activity was significantly lower for the bilateral injection group compared with the unilateral injection group (40.3% vs 75.9%, P < .05). Sites of visualized extraprostatic activity included the seminal vesicles (8 of 14 patients), internal iliac vessels (7 of 14 patients), bladder wall (5 of 14 patients), space of Retzius (3 of 14 patients), rectal wall (3 of 14 patients), and penis (1 of 14 patients).

CONCLUSIONS

Perfusion mapping with (99m)Tc-MAA can be effectively performed with SPECT/CT after selective prostate artery catheterization. The relative percentage of intraprostatic versus extraprostatic activity can be quantified, and the distribution of activity within and outside the prostate gland can be determined.

Targeted focal therapy for the management of organ confined prostate cancer

PURPOSE

Patients currently diagnosed with low risk prostate cancer are often overtreated and experience complications, resulting in detriment to quality of life. Targeted focal therapy is a minimally invasive procedure designed to ablate tumor foci while minimizing collateral damage to maintain quality of life.

MATERIALS AND METHODS

This institutional review board approved, prospective study was done to assess the safety and efficacy of targeted focal therapy using cryotherapy in men 40 to 85 years old diagnosed with low risk, organ confined prostate cancer at our institution between 2006 and 2009. Low risk, organ confined prostate cancer was defined as Gleason score 7 or less (3 + 4) on transrectal ultrasound biopsy, tumor burden 50% or less and prostate specific antigen less than 10 ng/dl. Patients were evaluated for eligibility after undergoing 3-dimensional mapping biopsy. Median followup was 28 months (IQR 26-31).

RESULTS

A total of 62 men with low risk disease met study inclusion criteria. At 1 year biopsy was negative in 50 of 62 patients (81%). All 12 men who tested positive on repeat biopsy had a Gleason score of 3 + 3 = 6 with 1 or 2 positive cores. The median prostate specific antigen change was a 3.0 ng/dl decrease (p <0.01). The median American Urological Association symptom score change was a 1.5-point decrease (p <0.01). No significant change was observed in Sexual Health Inventory for Men score (p = 0.6). No urinary incontinence episodes and no severe side effects were noted.

CONCLUSIONS

Targeted focal therapy in carefully selected patients provides a feasible, practical option for treating low risk prostate cancer with minimal impact on quality of life.

Low temperature plasma: a novel focal therapy for localized prostate cancer?

Despite considerable advances in recent years for the focal treatment of localized prostate cancer, high recurrence rates and detrimental side effects are still a cause for concern. In this review, we compare current focal therapies to a potentially novel approach for the treatment of early onset prostate cancer: low temperature plasma. The rapidly evolving plasma technology has the potential to deliver a wide range of promising medical applications via the delivery of plasma-induced reactive oxygen and nitrogen species. Studies assessing the effect of low temperature plasma on cell lines and xenografts have demonstrated DNA damage leading to apoptosis and reduction in cell viability. However, there have been no studies on prostate cancer, which is an obvious candidate for this novel therapy. We present here the potential of low temperature plasma as a focal therapy for prostate cancer.

Pubic bone osteomyelitis after salvage high-intensity focused ultrasound for prostate cancer

High-intensity focused ultrasound can be used for the primary treatment of prostate cancer and biochemical recurrence after radical prostatectomy or radiation. Complications of high-intensity focused ultrasound include urinary retention, urethral stenosis, stress incontinence, urinary tract infections, dysuria, impotence, and rarely, rectourethral or rectovesicular fistula. We describe a patient presenting with urinary retention, urinary tract infections and intermittent stress incontinence, later found to be associated with pubic bone osteomyelitis stemming from a prostatopubic fistula.

TOOKAD(®) Soluble vascular-targeted photodynamic (VTP) therapy: determination of optimal treatment conditions and assessment of effects in patients with localised prostate cancer

OBJECTIVES

To evaluate the optimal treatment conditions and effects of TOOKAD(®) Soluble vascular-targeted photodynamic (VTP) therapy in patients with localised prostate cancer. To evaluate the safety and quality of life after TOOKAD(®) Soluble VTP treatment in patients with localised prostate cancer.

PATIENTS AND METHODS

Men (aged >18 years) diagnosed with localised prostate cancer, who were suitable for active surveillance, were invited to take part in the study. Patients who had received prior or current treatment for their cancer were excluded. There were two parts to the study: in part one, patients were assigned to one of two treatment groups based on the size of their prostates (patients with prostate size <60 mL would receive 4 mg/kg TOOKAD(®) Soluble and patients with prostate size ≥60 mL would receive 6 mg/kg TOOKAD(®) Soluble both activated with 200 J/cm light). In part two, patients were assigned to one of two treatment groups based on predefined criteria and received either 4 or 6 mg/kg TOOKAD(®) Soluble and 200 or 300 J/cm light. VTP was conducted under general anaesthesia using TOOKAD(®) Soluble administered intravenously and activated by light-diffusing fibres within the prostate via the perineum. Follow-up was conducted for 6 months. Magnetic resonance imaging (MRI) carried out at 1 week after VTP and transrectal prostate biopsy at 6 months were the key endpoints. Adverse event (AE) recording and patient-reported outcome measures were collected.

RESULTS

In all, 86 patients were enrolled in the study and 85 patients received treatment. Of the 85 treated patients, one patient discontinued (due to withdrawal of consent). At 6 months, 61/83 (74%) patients who underwent prostate biopsy had histopathology that was negative for prostate cancer (95% confidence interval (CI) 62.7-82.6%). Considering patients who received 4 mg/kg TOOKAD(®) Soluble and 200 J/cm light (unilateral), which are considered optimal treatment parameters, 38/46 (83%) patients had histopathology from the biopsies that was negative for prostate cancer at 6 months (95% CI 68.6-92.2%; P < 0.001). The mean percentage of necrosis of the targeted prostate tissue at 7 days after VTP was 78% overall (83 patients) with extraprostatic necrosis reported in 76% (63/83) of patients. Considering patients who received 4 mg/kg TOOKAD(®) Soluble and 200 J/cm light (unilateral), the mean 7-day necrosis percentage was 88% (46 patients) with extraprostatic necrosis reported in 72% (33/46) of patients. All occurrences of extraprostatic necrosis were considered clinically acceptable and none were associated with any clinical sequelae. The mean percentage prostate necrosis at 7 days was statistically significantly higher (P < 0.001) in patients treated with a therapeutic light density index (LDI) of ≥1 than those treated with a LDI of <1. The percentage of patients with negative biopsies at 6 months was also higher in patients treated with a therapeutic LDI of ≥1 than those treated with a LDI of <1 (78.6% and 63.0%, respectively). In all, 87% (75/86) of patients reported at least one treatment-emergent AE during the study. Most AEs were mild or moderate in intensity and considered related to the technical procedures of the study. No treated patients had hypotension or discontinued due to AEs. Eight patients (9.3%) had serious AEs; none resulted in discontinuation from the study.

CONCLUSIONS

Biopsy data, post-treatment dynamic contrast-enhancement MRI at 1 week after VTP and analysis of the safety data have shown that 4 mg/kg TOOKAD(®) Soluble and 200 J/cm light are the optimal treatment conditions for the VTP procedure resulting in >80% of patients treated with this regimen having a negative biopsy at 6 months. Overall, the treatment was well tolerated and exhibited early signs of efficacy for minimally invasive focal treatment of localised prostate cancer.

The role of targeted focal therapy in the management of low-risk prostate cancer: update on current challenges

Prostate cancer is one of the most prevalent cancers among men in the United States, second only to nonmelanomatous skin cancer. Since prostate-specific antigen (PSA) testing came into widespread use in the late 1980s, there has been a sharp increase in annual prostate cancer incidence. Cancer-specific mortality, though, is relatively low. The majority of these cancers will not progress to mortal disease, yet most men who are diagnosed opt for treatment as opposed to observation or active surveillance (AS). These men are thus burdened with the morbidities associated with aggressive treatments, commonly incontinence and erectile dysfunction, without receiving a mortality benefit. It is therefore necessary to both continue investigating outcomes associated with AS and to develop less invasive techniques for those who desire treatment but without the significant potential for quality-of-life side effects seen with aggressive modalities. The goals of this paper are to discuss the problems of overdiagnosis and overtreatment since the advent of PSA screening as well as the potential for targeted focal therapy (TFT) to bridge the gap between AS and definitive therapies. Furthermore, patient selection criteria for TFT, costs, side effects, and brachytherapy template-guided three-dimensional mapping biopsies (3DMB) for tumor localization will also be explored.

Morbidity of focal therapy in the treatment of localized prostate cancer

BACKGROUND

Focal therapy (FT) for prostate cancer (PCa) seems to be part of a natural evolution in the quest to improve the management of early organ-confined disease.

OBJECTIVE

To assess the morbidity of the initial experience of FT in a tertiary referral center for PCa management.

DESIGN, SETTING, AND PARTICIPANTS

From 2009 to 2011, a total of 1213 patients with clinically localized PCa were treated at our institution. Of these patients, 547 were considered to have indolent disease according to the D'Amico criteria for low-risk disease plus unilateral disease with a maximum of three positive biopsies. A total of 106 patients underwent FT using high-intensity focused ultrasonography (HIFU), brachytherapy, cryotherapy, or vascular-targeted photodynamic therapy (VTP).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Complications were prospectively recorded and graded according to the Clavien-Dindo scale. Data were prospectively collected and retrospectively analyzed.

RESULTS AND LIMITATIONS

This study included 106 patients, median age 66.5 yr (interquartile range [IQR]): 61-73), who had a prostate hemiablation; 50 patients (47%) had cryotherapy, 23 patients (22%) had VTP, 21 patients (20%) received HIFU, and 12 patients (11%) had brachytherapy. The median prostate-specific antigen (PSA) level was 6.1 ng/ml (IQR: 5-8.1), all the patients had a biopsy Gleason score of 6, and the median prostate weight was 43 g (IQR: 33-55). The median International Prostate Symptom Score was 6 (IQR: 3-10), and the median International Index of Erectile Function score was 20 (IQR: 15-23). After treatment, the median PSA at 3, 6, and 12 mo was 3.1 2.9, and 2.7 ng/ml (IQR: 2-5.1, 1.1-4.7, and 1-4.4), respectively. Thirteen percent of the patients experienced treatment-related complications. There were 11 minor medical complications (10 grade 1 complications and 1 grade 2 complication), 2 grade 3 complications, and no grade 4 or higher complications.

CONCLUSIONS

FT for a highly selected population with PCa is feasible and had an acceptable morbidity with <2% major complications.