Stereotactic Radiosurgery for Prostate Cancer Following Magnetic Resonance Imaging Directed Biopsy: A Multidisciplinary Approach with Case Examples.

Classically, prostate cancer has been diagnosed via systematic, transrectal ultrasound-guided biopsy prompted by an abnormal digital rectal exam or elevated serum prostate-specific antigen (PSA) level. The development of multi-parametric magnetic resonance imaging (MRI) has led to improved detection of prostate cancer foci. For patients with clinically localized prostate cancer seeking definitive therapy through radiation therapy, external beam radiation has been a mainstay with a movement toward hypofractionation, notably prostate stereotactic body radiotherapy (SBRT). We aim to describe the practical aspects of establishing a multidisciplinary, MRI-based prostate SBRT program by means of case examples. The prostate SBRT team at the University of Alabama at Birmingham has been performing prostate SBRT for over four years using a multidisciplinary workflow. We have additionally completed a phase II trial of prostate SBRT with additional targeting of intraprostatic lesions with higher doses of radiation using a simultaneous integrated boost technique. While there have been no reported randomized trials of prostate SBRT, this treatment has been proven safe and effective for properly selected patients with low and intermediate-risk prostate cancer. We present our multidisciplinary approach to prostate SBRT with two clinical cases targeting high-risk [MAM1] lesions in different anatomic zones of the prostate highlighting pertinent clinical challenges in successfully delivering prostate SBRT and managing potential side effects. In conclusion, we report a multidisciplinary, MRI-based approach to treating patients with ultra hyperfractionated stereotactic radiosurgery as primary definitive treatment for prostate cancer.