For patients who choose to proceed with radiation therapy for the treatment of their prostate cancer, stereotactic body radiotherapy (SBRT), intensity modulated radiotherapy (IMRT) and brachytherapy are the potential treatment options. With advancements in technology, SBRT has become used more popular due to its effectiveness, convenience (5 treatments compared to 45 treatments with IMRT) and lower risk of side effects.

A large multi-institutional study of 803 patients with prostate cancer treated with SBRT, IMRT and brachytherapy compared the patient-reported quality of life outcomes of the three treatment options (Evans et al, Radiotherapy & Oncology 2015). The study found that SBRT had a lower risk of gastrointestinal side effects (diarrhea, rectal bleeding, etc.) than either IMRT or brachytherapy. Another key finding of the study was that brachytherapy had the highest risk of urinary side effects (pain with urination, urinary frequency, etc.) and that both SBRT and IMRT had a low risk of causing urinary dysfunction. There were no differences in sexual dysfunction between the three treatments.

While SBRT, IMRT and brachytherapy are all effective treatment options, more patients are choosing SBRT due to the effectiveness, convenience and lower risk of side effects with CyberKnife.

For further information, please contact our office at (907) 212-3186 to schedule a consultation with one of our Radiation Oncologists.


Stereotactic body radiation therapy (SBRT) – also sometimes referred to as stereotactic radiosurgery (SRS) – is one of the most advanced form of radiation therapy for cancer treatments. SBRT and SRS are techniques used in radiation therapy to destroy diseased tissue by precisely directing very high doses of radiation, while avoiding healthy surrounding tissue, critical structures and organs. SBRT commonly is used for treating tumors throughout the body, while SRS is used to describe treatments specific to the head and neck.

Unlike conventional radiation therapy (IMRT, IGRT and proton therapy, which can require 35 or more consecutive days of treatments), SBRT and SRS treatments are given once per day for 5 days or fewer.

Conventional radiation treatments for prostate cancer face a challenge delivering radiation to the prostate tumors because the prostate, and the tumor itself, move involuntarily in response to body functions. Leveraging its SBRT and SRS functionality, the CyberKnife System solves this problem by tracking tumor movements. Doctors use fiducial markers – tiny gold seeds inserted into the prostate with a needle – to help the CyberKnife System keep track of the tumor’s position, even as it moves.

Then, throughout the treatment process, the CyberKnife System takes digital images to ensure that each radiation beam is aimed directly at the tumor. The system also adjusts to regular movement of the tumor and patient’s body to ensure treatment remains on target, sparing healthy tissue.

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