Dose Escalation for Prostate Cancer Using Oligofractionated, Stereotactic Ablative Radiotherapy

Abstract

Radiation therapy is a standard of care option for the definitive management of low- and intermediate-risk prostate cancer, and is a critical component of both definitive and multimodality therapy for high-risk prostate cancer. For years, increasingly higher cumulative doses of conventionally-fractionated (1.8–2 Gy per fraction) radiation therapy have been associated with improved biochemical recurrence free survival, at the cost of increasing treatment duration and expense, and decreased convenience for patients. There is mounting evidence that a subset of hypofractionated regimens, called oligofractionated (oligo = few), stereotactic ablative radiation therapy (SAbR; also referred as stereotactic body radiation therapy, SBRT), may be clinically equally or perhaps more effective in the management of prostate cancer as a protracted course. While SAbR-like fractionation has been reported for decades, the current form is more apt to avoid toxicity by using modern technological advances in imaging, dosimetry and radiation delivery. In addition to a high likelihood of durable biochemical control, this form of treatment is far more convenient for patients, and potentially reduces the overall cost of therapy. Recent clinical trials have shown excellent outcomes in properly selected patients. This chapter will discuss the use of oligofractionation in radiation therapy to improve oncologic outcomes in the management of localized prostate cancer.