Radiation therapy has played a significant role in the management of prostate cancer for over half a century. High-energy megavoltage linear accelerators developed in the 1950s provided deeper penetration of tumoricidal dose, superficial tissue sparing and hence lower morbidity profiles than earlier models. The introduction of the CT scanner and complex computer-based treatment planning software in the 1980s improved three-dimensional target localization and enhanced accuracy. Subsequently, intensity-modulated treatment planning capabilities enabled highly conformal dose escalation for improved outcomes without added toxicity. New image-guidance techniques have further refined treatment delivery by compensating for internal organ variability. Concurrent with vast improvements in external beam radiation therapy, modern brachytherapy methods, facilitated by dynamic imaging, have become sophisticated and popular techniques for primary as well as salvage therapies. In addition, refinement of prognostic factors, particularly prostate-specific antigen (PSA), and contemporary imaging for staging have substantially improved patient selection for individualized therapy.
Today, modern radiotherapeutic approaches rely on accurate staging, precise imaging, and prognostic prediction, as well as technical advances in dose delivery and normal tissue protection.
Imaging for patient selection and radiation treatment planning
An accurate staging assessment prior to definitive therapy is critical in order to maximize cure rates. Prognostic risk factors including American Joint Commission on Cancer (AJCC) stage, Gleason score and pre-treatment PSA assess the risk of disease beyond the prostate, predict the yield of diagnostic studies, and guide radiotherapeutic decision-making.