Evolution of Image Guidance and Adaptive Radiation Therapy for Localized Prostate Cancer.

Radiation therapy (RT) has played a pivotal role in managing prostate cancer over the past 5 decades, undergoing significant transformations to optimize therapeutic efficacy and minimize toxicity. Advances in radiobiologic understanding and technological innovation have shifted RT practices, enabling precision in dose delivery and enhanced protection of adjacent normal tissues. This review examines the evolution of RT techniques, from early 2-dimensional planning to modern adaptive approaches that incorporate real-time imaging adjustments. With the introduction of 3-dimensional conformal RT, intensity modulated RT, volumetric modulated arc therapy, and image guided techniques, the safety and efficacy of RT have improved dramatically, reducing gastrointestinal and genitourinary toxicities and expanding its indications to include localized, recurrent, and metastatic prostate cancer. Today, online adaptive RT, supported using computed tomography and magnetic resonance imaging guidance, allows for precise dose modifications that align with daily anatomic changes, thus advancing the therapeutic ratio further. This review details these advancements, highlighting their impact on local control, patient outcomes, and future implications for RT in prostate cancer treatment.