Study of Hypo-fractionated Proton Radiation for Low Risk Prostate Cancer

Inclusion Criteria:

- Histologically confirmed prostate adenocarcinoma within 365 days prior to
randomization.

- History/physical examination with digital rectal examination of the prostate and
baseline toxicity assessment within 90 days prior to randomization.

- Histological evaluation of prostate biopsy with assignment of a Gleason score to the
biopsy material;Gleason score must be in the range of 2-6. > 6 cores are strongly
recommended.

- PSA values < 10 ng/ml within 90 days prior to randomization. Either done prior to
biopsy or at least 21 days after prostate biopsy.

- Clinical stages T1a-T2a N0 M0 (AJCC Criteria 7th Ed.). Staging must be done by
treating investigator.

- No pelvic lymph nodes > 1.5 cm in greatest dimension unless the enlarged lymph node is
biopsied and negative.

- Patients must be at least 18 years old.

- ECOG performance status 0-1 (appendix I) documented within 90 days prior to
randomization.

- IPSS score <= 16.

- Patients must give IRB approved, study specific, informed consent.

- Patients must complete all mandatory tests listed in section 4.0 within the specified
time frames.

- Patients must be able to start treatment within 56 days of randomization.

Exclusion Criteria:

- Previous prostate cancer surgery to include: prostatectomy, hyperthermia and
cryosurgery.

- Previous pelvic radiation for prostate cancer.

- Androgen deprivation therapy prior to radiation is allowed. However, it is not
acceptable if continued during radiation or as adjuvant therapy.

- Active rectal diverticulitis, Crohn's disease affecting the rectum, or ulcerative
colitis.

- Prior systemic chemotherapy for prostate cancer.

- History of proximal urethral stricture requiring dilatation.

- Current and continuing anticoagulation with warfarin sodium (Coumadin, heparin,
low-molecular weight heparin, Clopidogrel bisulfate (Plavix),or equivalent. (Unless it
can be stopped to manage treatment related toxicity, to have a biopsy if needed, or
for marker placement).

- Any major medical, addictive or psychiatric illnesses which would affect the consent
process, completion of treatment and/or interfere with follow-up. Consent by legal
authorized representative is not permitted in this study.

- Evidence of any other cancer within the past 5 years and < 50% probability of a 5 year
survival. (Prior or concurrent diagnosis of basal cell or non-invasive squamous cell
cancer of the skin is allowed).