Proton Beam Therapy in Prostate Cancer: Clinical Evidence, Controversies and Future Directions

Area of Science:

• Radiation Oncology
• Medical Physics
• Oncology

Background:

• Proton beam therapy (PBT) offers precise dose delivery with a Bragg peak, sparing normal tissues.
• Its application in prostate cancer (PCa) requires evaluation of clinical, dosimetric, and radiobiological evidence.

Purpose of the Study:

• To review and assess PBT's effectiveness for localized and locally advanced prostate cancer.
• To evaluate treatment toxicity, oncological outcomes, and future research directions.

Main Methods:

• Narrative review of clinical, dosimetric, and radiobiological studies.
• Analysis of prospective and retrospective cohorts, meta-analyses, and observational studies.
• Consideration of ongoing randomized trials and technological advancements.

Main Results:

• PBT demonstrates reduced dose to the bladder and rectum.
• Low rates of severe genitourinary/gastrointestinal toxicity and preserved quality of life are reported.
• Meta-analyses show modest acute gastrointestinal event reductions but similar 5-year biochemical control compared to IMRT/VMAT.

Conclusions:

• PBT offers dosimetric advantages, but clear clinical superiority over IMRT/VMAT is not consistently demonstrated.
• Radiobiological uncertainties and limitations in current literature necessitate careful patient selection.
• Further randomized trials are crucial to establish PBT's role in routine prostate cancer treatment.