Late Toxicities of Prostate Radiotherapy: Can We Further SMARTen Up the Therapeutic Index?

Radiotherapy is a mainstay treatment option for localized prostate cancer (PCa), with oncological outcomes similar to those with surgery. Standard-of-care radiotherapy approaches include brachytherapy, hypofractionated external beam radiotherapy (EBRT), and EBRT with brachytherapy boost. Given the long survival associated with PCa and these curative-intent radiotherapy approaches, late toxicity is a paramount consideration. In this narrative mini-review, we summarize late toxicities associated with standard-of-care radiotherapy approaches including stereotactic body radiotherapy, an advanced radiotherapy technique supported by accumulating evidence. We also discuss stereotactic magnetic resonance imaging-guided adaptive radiotherapy (SMART), an emerging paradigm that may further improve the therapeutic index of radiotherapy and reduce late toxicities. PATIENT SUMMARY: This mini-review summarizes late side effects associated with standard and advanced radiotherapy techniques for localized prostate cancer. We also discuss a new radiotherapy approach called SMART that may reduce late side effects and increase treatment effectiveness.