Effectiveness of the SpaceOAR Vue System in Subjects With Prostate Cancer Being Treated With Stereotactic Body Radiotherapy

Inclusion Criteria:

• Age ≥ 18 years old.

• Subjects must have pathologically confirmed (by routine hematoxylin and eosin (H&E)staining) invasive adenocarcinoma of the prostate and been planning to undergo SBRT.

• Subjects must have intermediate risk prostate cancer as defined by the presence ofone or more of the following:

• Clinical Stage T2b - T2c (AJCC 6th edition) tumor

• Gleason Score 7 as determined from a biopsy taken within 9 months precedingEnrollment (randomization)

• Demonstrated blood PSA levels 10-20 ng/ml as measured within 6 months precedingEnrollment (randomization) and prior to commencing androgen deprivation therapy (ADT)

• Subject or authorized representative was informed of the nature of the study andprovided written informed consent, approved by the appropriate Institutional ReviewBoard (IRB)/Ethics Committee (EC) of the respective clinical site.

Exclusion Criteria:

• Prostate >80 cc documented within 9 months preceding Enrollment (randomization)

• Clinical stage T3 or T4 (AJCC 6th edition) tumor

• Blood PSA level >20 ng/ml as measured within 6 months preceding Enrollment (randomization) and prior to commencing androgen deprivation therapy (ADT)

• Gleason Score ≥ 8 as determined from a biopsy taken within 9 months precedingEnrollment (randomization)

• Subjects who had MRI evidence of gross posterior extracapsular extension (ECE) ofthe prostate cancer. (Note: MRI should be from within 9 months preceding Enrollment (randomization). If MRI is contraindicated, a digital rectal exam may be performedto confirm the absence of gross posterior ECE)

• Subjects who had metastatic disease, other ongoing cancers which were treated duringthe study or subjects for whom pelvic lymph node radiotherapy was planned.

• Subjects with any prior invasive malignancy (except non-melanomatous skin cancer)unless the subject had been disease free for a minimum of 3 years.

• History of prostatectomy, transurethral prostate surgery (e.g. TUNA, TUMT, TURP) ifperformed within 1 year prior to screening, other local prostate cancer therapy (e.g., cryotherapy or brachytherapy) or previous pelvic irradiation at any timeprior to screening.

• History of prior pelvic surgery requiring low anterior or abdominoperinealresections or rectal surgery.

• History of or active inflammatory bowel disease (IBD) such as Crohn's disease orulcerative colitis.

• History of or current perirectal disease that may interfere with interpretation ofstudy outcomes including anal or perianal diseases such as fistula.

• Bleeding hemorrhoids requiring medical intervention within the prior three months.

• Diagnosed active bleeding disorder or a clinically significant coagulopathy. Note:Patients on anticoagulants may be included if the anticoagulant medication can bediscontinued for index procedure.

• Active inflammatory or infectious process involving the perineum, gastrointestinal (GI) or urinary tract based on positive diagnosis or suspected diagnosis in thepresence of fever >38⁰ C, WBC > 12,000/uL.

• Compromised immune system or prior diagnoses for human immunodeficiency virus (HIV) (with a detectable viral load within the last 6 months)/acquired immunodeficiencysyndrome (AIDS) or autoimmune disease.

• If a subject was enrolled in another investigational drug or device trial that hadnot completed the primary endpoint or that clinically interfered with this study.

• Unable to comply with the study requirements or follow-up schedule.

• Any condition the Investigator believed would interfere with the intent of the studyor would make participation not in the best interest of the patient.

• Known iodine sensitivity or allergy

• Known polyethylene glycol (PEG) sensitivity or allergy