Focal Therapy for Localized Prostate Cancer: Promise, Progress, and Unanswered Questions
Key Insights
A special collection in *Prostate Cancer (search) and Prostatic Diseases* provides a comprehensive assessment of focal therapy (FT) for localized prostate cancer, highlighting mature evidence and emerging technologies.
Pooled data from 49 cohorts show excellent short- to intermediate-term oncological outcomes for HIFU (search), cryotherapy (search), and IRE, with overall and cancer-specific survival rates approaching 99%.
Emerging modalities including MRI-guided focused ultrasound, TULSA (search), focal laser ablation (search), and histotripsy (search) demonstrate encouraging efficacy with excellent functional preservation, though long-term data remain limited.
The landscape of localized prostate cancer (search) (PCa) treatment is undergoing a significant transformation, driven by earlier diagnosis and a growing emphasis on preserving quality of life. A special collection published in Prostate Cancer and Prostatic Diseases (PCAN), developed in collaboration with the Société Internationale d'Urologie, offers a timely and comprehensive overview of where focal therapy (FT) stands—from mature evidence on established modalities to the emergence of novel energy platforms and the increasingly critical role of salvage strategies.
As the urological community increasingly studies ablative technologies for organ-confined disease, FT has emerged as a promising alternative to radical whole-gland treatments. By targeting only the index lesion—considered the main driver of disease progression—FT seeks to minimize damage to surrounding structures and reduce treatment-related morbidity, including urinary, sexual, and bowel dysfunction that commonly accompany radical prostatectomy or radiotherapy.
Established Modalities Deliver Reassuring Oncological Outcomes
One of the most significant contributions to the collection is a systematic review and meta-analysis by Tay et al., which pools data from 49 cohorts spanning more than a decade of clinical experience with high-intensity focused ultrasound (HIFU (search)), cryotherapy (search), and irreversible electroporation (search) (IRE). The findings are highly reassuring: pooled overall survival, cancer-specific survival, and metastasis-free survival rates all approach 99%. Biochemical progression was reported in only 30% of the cohorts, with a mean annual biochemical progression rate of 9%.
No significant differences were observed among the three modalities or across FT ablation patterns, though the authors noted a temporal shift toward more focal and targeted ablation strategies compared with earlier hemi-ablation approaches. Using a composite failure endpoint—including radical or whole-gland treatment, initiation of hormonal therapy, or transition to watchful waiting, while excluding repeat FT procedures—19 of 38.8% of cohorts reported a pooled failure rate of 14%.
Despite these encouraging results, the heterogeneity in surveillance protocols, treatment margins, and follow-up biopsy strategies remains a major limitation, underscoring the urgent need for standardized clinical pathways.
Emerging Technologies Show Early Promise
The review by Ghai et al. examines the "new kids on the block": MRI-guided focused ultrasound, transurethral ultrasound ablation (TULSA (search)), focal laser ablation (search) (FLA), and histotripsy (search). MRI-guided approaches are particularly compelling because they offer real-time thermal monitoring, precise treatment margins, and potentially superior reproducibility.
MR-guided focused ultrasound surgery (MRgFUS) is a non-invasive technique that uses focused ultrasound waves under real-time MRI guidance to induce thermal coagulative necrosis. TULSA (search) delivers directional ultrasound energy through a transurethral applicator under MRI thermometry guidance, enabling controlled whole-gland or subtotal ablation. FLA uses laser-induced thermal energy for highly localized tissue destruction. Histotripsy (search), a novel non-thermal technology, mechanically fractionates tissue through cavitation bubble activity while potentially preserving surrounding extracellular structures.
These modalities have demonstrated encouraging oncological efficacy together with excellent functional preservation, particularly regarding continence and erectile function. However, most available studies are small, non-randomized, single-center series with relatively short follow-up. MRI-guided procedures are associated with increased procedural complexity, longer operative times, and higher costs.
Imaging: The Cornerstone and the Bottleneck
Across all studies, multiparametric MRI (mpMRI) emerges as the cornerstone of focal therapy, extending beyond diagnosis to include lesion localization, treatment planning, margin definition, and post-treatment surveillance. Correas et al. examined the potential added value of multiparametric ultrasound (mpUS) and micro-ultrasound (mUS), noting that shear wave elastography (SWE) improves detection of stiff lesions not seen with other imaging techniques, with accuracy, sensitivity, and negative predictive value ranging from 70 to 96%, 92 to 96%, and 83 to 99%, respectively.
Yet a critical counterargument persists: if the imaging modality used to define the treatment target fails to identify all clinically significant disease—and mpMRI misses secondary clinically significant prostate cancer (search) in up to 50% of cases—then the biological rationale of FT becomes weaker. As the authors emphasize, the limitation is not the ablation technology itself, but the ability to accurately map the disease before treatment.
The Biopsy Conundrum
Windisch et al. address the challenge of patient selection in their narrative review, noting that MRI-targeted biopsy combined with systematic TRUS biopsy achieved approximately 80% sensitivity and 75% overall accuracy for FT eligibility when compared with whole-mount histopathology. However, nearly half of patients initially considered eligible for FT based on MRI-targeted biopsies were later deemed unsuitable after final pathology assessment, mainly due to undetected contralateral or more extensive disease. While transperineal template mapping biopsy (TTPM) offers improved staging accuracy, it requires general anesthesia and carries higher morbidity.
Genomic Biomarkers: Potential Yet Unproven
Ghoreifi et al. explore whether genomic biomarkers—including Decipher (search), Oncotype DX Genomic Prostate Score (search), and Prolaris (search)—can improve patient selection beyond conventional clinical, imaging, and pathological variables. While these assays have demonstrated prognostic value for adverse pathology, biochemical recurrence, metastasis, and prostate cancer (search)-specific mortality, most have been validated in cohorts undergoing active surveillance, radical prostatectomy, or radiotherapy rather than FT. There is currently no prospective evidence demonstrating that adding genomic classifiers to contemporary MRI-guided patient selection translates into improved oncological outcomes.
Managing Recurrence: An Underexplored Frontier
Ramacciotti et al. address one of the most clinically relevant and underexplored issues: what happens when focal therapy fails? Their review of 21 studies encompassing 1,012 patients found that the most reported salvage treatments were salvage radical prostatectomy followed by re-do ablation therapy, while only one study evaluated salvage radiation therapy. Oncological outcomes showed acceptable biochemical recurrence rates, though functional outcomes varied, with significant impacts on erectile function across modalities.
Critically, the primary endpoint of FT in prostate cancer (search) remains undefined. Proposed endpoints include biochemical recurrence-free survival, absence of detectable lesions on imaging or biopsy, avoidance of radical or systemic treatment, absence of metastasis, and prostate cancer-specific mortality. Expert consensus has defined FT success more strictly as complete eradication of all biopsy-proven clinically significant disease (Gleason Grade ≥2 lesions), yet this creates a conceptual mismatch, as patients with low-volume GG2 disease may still be appropriately managed with active surveillance.
The Road Ahead
Focal therapy is no longer an experimental niche but an increasingly mature field in uro-oncology. Current evidence supports its use in intermediate-risk patients, while active surveillance remains preferable in low-risk disease. Major guidelines still recommend that FT, even with established modalities, should be performed at least within a prospective registry. The challenge ahead is no longer proving feasibility, but defining durability, standardization, and patient selection. As the collection makes clear, the road to success for focal therapy is paved by improvements in enhanced prostate imaging.