Narrative review of focal boost to intraprostatic dominant lesion in intensity-modulated radiation therapy for localized or locally advanced prostate cancer.

Local intraprostatic recurrence is one of the important recurrence patterns following definitive intensity-modulated radiation therapy (IMRT) that continues to pose a significant challenge. The technological advances in radiation therapy now facilitate selective dose escalation for intraprostatic dominant lesions (IPDLs). A novel IMRT method, focal boosting using simultaneous integrated boost IMRT (FB-SIB-IMRT), can achieve selective dose escalation to IPDLs while minimizing any increase in dose to organs at risk (OARs). In addition, this method is applied to hypofractionated EBRT, including stereotactic body radiation therapy (SBRT). To date, numerous prospective studies have reported clinical results of FB-SIB-IMRT for non-metastatic PCa. In this review, we describe and summarize clinical outcomes of previous studies, including the technological background, current status, and future perspectives regarding focal dose escalation for IPDLs using IMRT for non-metastatic PCa.