MRI and Magnetic Resonance Spectroscopy Imaging in Patients Receiving Dutasteride for Benign Prostatic Hypertrophy and Low-Risk Prostate Cancer

OBJECTIVES:

Primary

• To determine whether there is a decrease in the extent of prostate cancer as measured by endorectal MRI and magnetic resonance spectroscopy imaging in patients with symptomatic benign prostatic hypertrophy and low-risk prostate cancer treated with dutasteride for 6 months.

Secondary

• To monitor the effects of dutasteride on serum testosterone, dihydrotestosterone, and free and total prostate-specific antigen (PSA).
• To monitor the effects of dutasteride on symptom and quality-of-life indices.

OUTLINE: Patients receive oral dutasteride once daily for 6 months.

Patients undergo endorectal MRI and magnetic resonance spectroscopy imaging at baseline and at 1, 3, and 6 months.

Patients complete quality-of-life questionnaires using the International Index of Erectile Function Questionnaire, American Urological Association Symptom Index, Functional Alterations due to Changes in Elimination, and Spitzer Quality-of-Life Index at baseline and at 1, 3, and 6 months.

Inclusion criteria

• Histologically confirmed adenocarcinoma of the prostate

• Clinical stage T1b, T1c, or T2a disease
• Gleason score ≤ 6
• Maximal prostate-specific antigen (PSA) < 10 ng/mL
• Demonstrates intra-prostatic metabolite abnormalities, consistent with adenocarcinoma of the prostate (i.e., ≥ 3 voxels with magnetic resonance spectroscopy imaging [MRSI] scores 4-5) by baseline MRI and MRSI
• Has symptomatic benign prostatic hypertrophy and is currently undergoing watchful waiting OR opting to undergo permanent seed implant (i.e., brachytherapy), but requires neoadjuvant androgen suppression for prostate shrinkage
• No regional lymph node involvement
• No evidence of distant metastases
• Zubrod performance status 0-1
• Able to swallow and retain oral medications

Exclusion criteria

• Other prior or concurrent invasive cancer, other than localized basal cell or squamous cell carcinoma of the skin
• Contraindications to MRI/MRSI, including any of the following:

• Prostate biopsy (within the past 8 weeks) and any continued post-biopsy bleeding
• Rectal bleeding
• Anal fissures
• Rectal surgery (end-to-end anastomosis)
• Inflammatory bowel disease
• Prior radical prostatectomy
• Hip replacement
• Certain types of penile implants
• Vascular clips
• Known anaphylactic reaction to latex compounds
• Anticoagulant drugs
• Severe claustrophobia
• Cardiac pacemaker
• Metal in eye
• Any other metallic or foreign object in the body
• Unstable serious co-morbidities including, but not limited to, myocardial infarction, coronary artery syndrome, cardiac arrhythmias, symptomatic congestive heart failure, or cerebrovascular accident
• Major medical or psychiatric illness that, in the investigator's opinion, would preclude the completion of treatment and interfere with follow up
• Known hypersensitivity to any 5α-reductase inhibitor or drug chemically related to the study drug
• Prior radical surgery (prostatectomy) or cryosurgery for prostate cancer
• Prior pelvic irradiation, prostate brachytherapy, or bilateral orchiectomy
• Prior or concurrent cytotoxic chemotherapy for prostate cancer
• Prior hormonal therapy, such as luteinizing hormone-releasing hormone agonists (e.g., goserelin or leuprolide acetate), antiandrogens (e.g., flutamide or bicalutamide), or estrogens (e.g., diethylstilbestrol)
• Prior or concurrent finasteride, dutasteride, other drugs with known antiandrogenic properties (e.g., spironolactone or progestational agents), or any dietary or herbal supplement (e.g., selenium, vitamin E, saw palmetto, or PC-SPES)