Inclusion Criteria:

Men who satisfy all of the following conditions will be eligible for this study:

- Willing and capable to provide informed consent

- Signed study specific informed consent form.

- PSA ≤ 20 prior to hormone therapy (if given) for patients with Gleason 2-6. For
those with Gleason score of 7. PSA should be less than or equal to 15 ng/ml prior to
hormonal therapy (if given). Thus, risk of pelvic lymph node involvement according to
Roach formula would be under 20%.

- Gleason score ≤ 7

- Appropriate staging studies identifying as AJCC stage T1a, T1b, T1c, T2a, or T2b

- No direct evidence of regional or distant metastases after appropriate staging
studies

- Histologic confirmation of cancer by biopsy

- Adenocarcinoma of the prostate

- Age ≥ 18

- Zubrod Performance Status 0-2

- Up to 9 months of previous hormonal therapy is allowed (but not required)

- AUA score must be ≤ 15 (alpha blockers allowed)

- CT or Ultrasound-based volume estimation of prostate gland ≤ 60 grams

- Agreement to use effective contraceptive methods such as condom/diaphragm and
spermicidal foam, intrauterine device, or prescription birth control pills.

Exclusion Criteria:

Women are not eligible for this study. Men with one or more of the following conditions
also are ineligible for this study:

- Positive lymph nodes or metastatic disease from prostate cancer

- Prior invasive malignancy unless disease free for a minimum of 3 years (carcinoma in
situ of the breast, oral cavity, or cervix, or non-melanomatous skin cancer are all
permissible)

- T2c, T3, or T4 tumors

- Previous pelvic radiotherapy

- Previous surgery or chemotherapy for prostate cancer

- Previous transuretheral resection of the prostate (TURP) or cryotherapy to the
prostate

- Previous hormonal therapy given for more than 9 months prior to therapy

- Concomitant antineoplastic therapy (including surgery, cryotherapy, conventionally
fractionated radiotherapy, and chemotherapy) while on this protocol.

- History of Crohn's Disease or Ulcerative Colitis.

- Previous significant obstructive symptoms; AUA score must be ≤ 15 (alpha blockers
allowed)

- Significant psychiatric illness

- Men of reproductive potential may not participate unless they agree to use an
effective contraceptive method.

- Ultrasound or CT estimate of prostate volume > 60 grams