Marieke van Son

177 GENERAL DISCUSSION AND FUTURE PERSPECTIVES Another limitation in primary focal therapy research is the wide variety of different modalities being used for focal ablation, creating a field in which we are reliant upon separate groups investigating (smaller) cohorts, often using non-uniform nomenclature, varying diagnostic work-up, follow-up protocols or study endpoints. Within the avail- able literature there are reports of focal HIFU, cryotherapy, brachytherapy, stereotactic body radiotherapy (SBRT), photodynamic therapy (PDT), irreversible electroporation (IRE), focal laser ablation (FLA), transurethral ultrasound ablation (TULSA) and radiof- requency ablation (RFA). For each energy modality, there are different techniques and/ or devices available, often with considerable technological differences. Furthermore, the minimal extent of ablation varies widely, from targeting the tumor with a margin to hemi-gland or “hockey stick” (three-quarters) ablation. Currently, there are no random- ized trials available comparing the outcome of different focal therapy technologies. The existing evidence from systematic reviews on the varying treatment strategies does not point to one approach being clearly superior to others(2-5). Figure 1 – Terminology for partial treatment of the prostate: “Focal therapy” versus “Partial gland ablation”. Image adapted from: Lebastchi et al., 2020(6) 10