Editorial Comment on Tay et al .

Focal therapy/partial ablation for prostate cancer now garners a lot of attention and controversy. Critics and skeptics point to the known multifocality nature of prostate cancer, countered by proponents of focal therapy with the “dominant index lesion versus secondary lesions” theory. Tay et al. used the cryo on line database (COLD) registry to retrospectively assess oncologic and functional outcomes of partial cryoablation, comparing with a propensity score matched group who had whole gland ablation. It should be emphasized that the authors selected for partial ablation only patients with low volume, intermediate risk disease.

“COLD” has the advantage of being a community-based registry, thus reflecting “real world” experience. Nevertheless, participation is voluntary and although data accuracy is strived for and rigorously ensured, some crucial technical factors (e.g., type of cryotherapy device used, patterns of cryoprobe placement, and extent of nerve sparing) vary among individual surgeons, likely affecting the robustness of the findings of this analysis.

The authors concluded that there was no difference in early biochemical disease-free survival. Emphasis should be placed on “early,” because median follow-up was relatively short. Another contentious issue is that only “for cause” biopsy was undertaken, thus only a small percentage of patients had histologic verification of “treatment success.” This is especially relevant in patients who had undergone partial ablation, leaving a significant portion of the prostate untreated.

On a broader topic of focal/partial prostate ablation as definitive therapy, there are numerous challenges: conceptual, technical (targeting precision/selectivity, reproducibility, and ideal ablative energies), and clinical (patient selection and follow-up). Indeed, there is no standardization for eligibility and exclusion criteria, nor for definition and metrics of “success” and “failure.” Limitations aside, this article has made a contribution to the literature. However, higher level evidence from studies addressing the aforementioned unresolved issues is needed to delineate the role of partial ablation in the management of localized prostate cancer.