Significant Impact of the Anterior Transition Zone Portion Treatment on Urinary Function After Focal Therapy with High-Intensity Focused Ultrasound for Prostate Cancer

Current status and future outlook of ultrasound treatment for prostate cancer

Radical prostatectomy and radiation therapy are the standard treatment options for localized prostate cancer (PC). However, radical prostatectomy may cause the deterioration of urinary and sexual function, and radiation-induced hemorrhagic cystitis and severe rectal bleeding are risk factors for fatal conditions in patients after radiation therapy. With the recent development of magnetic resonance imaging (MRI) for the localization of clinically significant PC (csPC) and treatment modalities, "focal therapy", which cures csPC while preserving anatomical structures related to urinary and sexual functions, has become a minimally invasive treatment for localized PC. Based on the clinical results of transrectal high-intensity focused ultrasound (HIFU) for localized PC in the whole gland and focal therapy, HIFU is considered an attractive treatment option for focal therapy. Recently, the short-term clinical results of transurethral high-intensity directional ultrasound (HIDU) have been reported. With the resolution of some issues, HIDU may be commonly used for PC treatment similar to HIFU. Because HIFU and HIDU have limitations regarding the treatment of patients with large prostate calcifications and large prostate volumes, the proper use of these modalities will enable the treatment of any target area in the prostate. To establish a standard treatment strategy for localized PC, pair-matched and historically controlled studies are required to verify the oncological and functional outcomes of ultrasound treatment for patients with localized PC.

Assessment after focal therapy: what is the latest?

PURPOSE OF REVIEW

To review assessment after focal therapy (FT) in the context of developments from the past two years.

RECENT FINDINGS

With a paucity of high-quality studies, recent findings are primarily reliant on results from institutional-based cohorts and reports of expert consensus. Notably, oncologic treatment failure should be further stratified into recurrence in the in-field or out-of-field ablation zone, and both regions should be surveilled postoperatively. Monitoring primarily consists of periodic evaluations of prostate-specific antigen (PSA) testing and magnetic resonance imaging, with histologic sampling needed to confirm suspicion of recurrence. Recent investigations into PSA derivatives, contrast-enhanced ultrasound, and prostate-specific membrane antigen imaging have shown preliminary promise. Although postablation functional outcomes are generally accepted to be excellent, they are limited by the wide range of patient-reported measures, variability in individual practice, and low questionnaire completion rates.

SUMMARY

There is still a need for high-level, long-term data to inform exact standardized protocols to manage patients after FT. A multifaceted approach is required to surveil patients and identify those at risk of recurrence. Embracing shared responsibility between the patient and clinician to fastidiously monitor the infield and out-of-field ablation zones postoperatively is critical to maximize oncologic outcomes.

Urethra-sparing surgery for a prostate cancer lesion in the anterior urethral zone with magnetic resonance-guided focused ultrasound: a case report

Prostate cancer (PCa) is the most common malignancy among men worldwide. High-intensity focused ultrasound (HIFU) is a focal therapeutic strategy for low- to intermediate-risk PCa with a low risk of complications. However, lesions located in the anterior urethral zone are challenging to treat with this approach because it is difficult to avoid urethral injury during HIFU therapy, which might further cause urethral stricture and symptoms related to bladder outlet obstruction (BOO). Here, we present the case of a 79-year-old male with elevated prostate-specific antigen (PSA) levels for over 1 year. Multiparametric magnetic resonance imaging revealed a 1.8 cm × 1.0 cm mass covering an area of the anterior urethral zone. Histopathological examination revealed an International Society of Urological Pathology grade group 3 acinar adenocarcinoma. Given the patient’s request for functional preservation, a magnetic resonance-guided focused ultrasound surgery was performed. During the operation, a urethra-sparing approach was utilized by administering proper energy and adjusting the sequence of the sonications. The patient developed urinary retention after catheter removal less than 48 h after the treatment, which resolved after removal of the second catheter a week later. On a follow-up visit 3 months after the treatment, evaluation by the level of PSA and multiparametric magnetic resonance imaging showed no recurrence of PCa. No significant changes in the International Prostate Symptom Score and Quality of Life score were found compared to baseline scores. With proper adjustment, magnetic resonance-guided focused ultrasound surgery could be safely used for urethra-sparing surgeries for PCa lesions in the anterior urethral zone, without influencing post-treatment urination. The indwelling time of the catheter should be extended appropriately for full recovery from treatment-related prostatic edema around the prostatic urethra to avoid urinary retention.

Development and future prospective of treatment for localized prostate cancer with high-intensity focused ultrasound

High-intensity focused ultrasound (HIFU) was experimentally used for focal therapy for anti-cancer effects in prostate cancer (PC). Focal therapy is a diagnosis-based investigational treatment option for localized PC that cures clinically significant PC (csPC) while preserving the anatomical structures related to urinary and sexual function based on its spread observed using multi-parametric magnetic resonance imaging (mpMRI). The European Association of Urology indicated that the current status of focal therapy for localized PC was an investigational modality and encouraged prospective recording of outcomes and recruitment of suitable patients in 2018. During the last few years, large-population multi- and single-center prospective studies have investigated focal therapy as a treatment strategy for localized PC. In a multicenter prospective study with 5-year follow-up, failure-free survival, which was defined as avoidance of local salvage therapy (surgery or radiotherapy), systemic therapy, metastases, and prostate cancer-specific death, was 88%. In the previous studies, there was no significant influence on urinary function before and at 3 months after the treatment, although transient impairment was reported 1 month after the treatment. Pad- and leak-free continence was preserved in 80-100% of the patients after treatment. Erectile function was significantly impaired in the initial 3 months after treatment compared to the pretreatment values, but it improved 6 months after the focal therapy in the previous reports. Paired comparison studies and cohort studies with long-term follow-up will contribute to verifying this treatment's clinical outcomes for patients with localized PC.