The investigators will compare tumor marker levels, including PSA, in samples taken from a peripheral upper limb vein and the internal iliac veins. These will be collected from patients who are scheduled for prostatectomy as part of their standard of care for prostate cancer. A selective internal iliac vein sampling procedure will be performed in Interventional Radiology. Venous samples will be correlated with prostatectomy specimens. The aim is to predict the side of the prostate containing tumor.

Inclusion Criteria:

1. All male patients, age 18 to 99, with biopsy proven prostate adenocarcinoma prior to planned radical prostatectomy.
2. Informed Consent/HIPAA Form discussed and signed by subject.
3. Baseline lab values obtained within 120 days of planned selective venous sampling.

Exclusion Criteria:

1. Skin related problems around the planned venepuncture site (infection, phlebitis, scars)
2. Documented allergy to iodinated contrast or lidocaine.
3. Coagulopathy with an INR of greater than 1.5
4. Thrombocytopenia with platelets less than 25,000 uL
5. Renal insufficiency with a creatinine of 1.5 mg/dL
6. Documented current upper extremity or central venous thrombosis
7. DRE within 4 weeks prior to selective venous sampling
8. Prostate biopsy within 6 weeks prior to selective venous sampling.
9. Patient unable to sign his own consent or does not demonstrate full understanding of the procedure.
10. Patient has known metastatic disease or a known primary cancer other than prostate adenocarcinoma.
11. Patient has already been enrolled in this research study.
12. Life expectancy less than 6 months.