Focal therapy (FT) is gaining ground as a viable option for treating localized prostate cancer, offering a middle path between active surveillance and radical interventions such as radical prostatectomy and radiation therapy. While radical treatments have been demonstrated with effective and predictable oncological outcomes, their related morbidities are not negligible. This includes urinary incontinence, erectile dysfunction, and radiation inducted gastrointestinal toxicities. To this end, FT has emerged as a minimally invasive modality, aiming to treat cancerous regions selectively and minimizing impact brought about by whole gland therapies. High-intensity focused ultrasound (HIFU) has been one of the most commonly studied and practised FT modalities. Focal HIFU works via delivering ultrasonic waves towards a malignant lesion. Heat above 65 °C is produced, destroying the targeted area through coagulative necrosis. This approach allows for better preservation of functional outcomes.

The study by Shoji and colleagues makes an important contribution to this evolving field [1]. Conducted over seven years, this multi-center prospective study offers a relatively long follow-up period, with patients monitored for a median of 48 months. The majority of HIFU literature had only described outcomes with follow-up durations within a 2-to-3-year time frame [2]. The extended observation period of the current literature provides valuable insights into the medium- to long- term durability of HIFU FT. An exceptional result was reported here, with a 7-year biochemical disease-free survival reaching 89.6% 88.5% and 81.6% for D’Amico low, intermediate and high risk diseases respectively.

One of the unique aspects of this study is its use of intraoperative transrectal prostate compression during the HIFU procedure. By applying pressure to the prostate, the shift of target region and the prostatic swelling were reduced. Manual force also compressed prostatic plexus, thereby reducing vascular flow and hence the heat-sink effect during HIFU treatment [3]. As a result, any incomplete destruction of lesion due to tissue inhomogeneities and asymmetrical heat conduction can be minimized [4, 5].

The inclusion of patients with high-grade but focal disease (specifically Gleason 4 + 4) is also noteworthy, as it demonstrated that even more aggressive forms of prostate cancer could be effectively managed with a targeted approach, provided the disease is localized and focal. The study also found that urinary and sexual functions, which initially declined after treatment, returned to pre-treatment levels within three to six months—a significant finding given the functional risks associated with conventional radical treatments.

To maximize the rates of technical and oncological success following FT and HIFU therapies, the following factors must be considered. First, patient selection is most important to ensure good outcomes following FT. Ideally, this approach should be reserved for men with unifocal or unilateral disease. Attempting to use FT in men with multifocal disease could lead to suboptimal results, both in terms of cancer control and functional preservation. Inferior oncological results with the need of early salvage treatment are expected when HIFU is being used to treatment multifocal high-risk disease. Functional results were also not typically beneficial when HIFU is adopted to treat bilateral disease, with significant urinary incontinence rates reported as up to 10% in meta-analysis of single arm studies [6]. Second, standardized follow-up protocols including routine biopsies should always be considered. In this study, the authors performed follow-up biopsies six months after treatment, which allowed them to assess the effectiveness of the HIFU therapy in eradicating clinically significant cancer. This echoes with expert consensus, which recommends biopsy being performed 6–12 months following FT, to allow time for the settlement of inflammatory and scar tissue [7]. It should be highlighted that standardized follow-up protocols also allow better comparisons between different studies, helping to build a stronger evidence base for FT. Third, FT is a highly specialized procedure that requires a high level of expertise. Surgeons performing HIFU need to be skilled in advanced imaging techniques, such as MRI-TRUS, to accurately locate and target the cancerous tissue. Centers offering FT must have not only the right technology but also the experience and procedural volume to ensure optimal outcomes. As FT becomes more widely available, it will be important to ensure that it is performed by dedicated and experienced teams who have the necessary expertise to deliver the best possible care.

In summary, this study by Shoji et al. demonstrated that HIFU with the use of intraoperative prostate compression could deliver outstanding oncological outcomes while minimizing functional morbidities effects, in a carefully selected cohort [1]. While the results of this study are promising, it is important to recognize the limitations of single-arm studies. To truly change clinical practice, we need level 1 evidence to support FT, and randomized trials that compare FT with other standard radical treatment options must be considered. One group of patients that would particularly benefit from such trials is men aged 75 and older. For this group of patients, a randomized trial comparing FT with radiotherapy could be especially informative. It would be fascinating to see if FT, with its more targeted approach, could strike an even better balance between oncological control and quality of life in this population.