Local dose escalation strategies in unfavourable intermediate- and high-risk prostate cancer: a comparative review of brachytherapy, SBRT and focal boost

This review discusses contemporary dose escalation strategies in unfavourable intermediate- and high-risk localised prostate cancer treated with external beam radiotherapy. It provides a clinically oriented comparison of three principal boost modalities: brachytherapy boost, stereotactic body radiotherapy (SBRT) boost and focal boosting of dominant intraprostatic lesions. The radiobiological rationale, key dosimetric characteristics and most important prospective and randomised clinical data are summarised to clarify how each approach affects biochemical control, toxicity and long-term outcomes. The review further outlines anatomical, functional and disease-related factors that influence boost selection, highlighting typical indications and relative contraindications for brachytherapy, SBRT and focal boosts. Particular emphasis is placed on patient selection in routine practice, integration with androgen-deprivation therapy and nodal irradiation, as well as logistical and resource considerations that affect real-world implementation. Remaining evidence gaps, including the need for head-to-head comparisons between boost techniques and for data on combinations with modern systemic treatment intensification, are also discussed. Overall, the article is primarily addressed to clinicians involved in prostate radiotherapy planning and decision-making, but may also be of interest to researchers developing future dose-escalation and personalisation strategies.