Stereotactic Body Radiation Therapy (SBRT) is a method of delivering radiation which can target the tumor more precisely and cause less damage to normal tissue. This is a Phase I research study looking at the safety of the dose of SBRT in organ confined prostate cancer.

Radiation options for treating early stage prostate cancer can include external radiation therapy, which is radiation given outside the body, or prostate seed implant, which is placing radioactive seeds directly into the prostate. For external beam radiation therapy, treatment can last up to 9 weeks. Treatment is given daily, Monday through Friday. This may not be the most convenient option for some patients.

One way to potentially overcome this challenge is to deliver a more intense dose of radiation treatment to the tumor over a shorter amount of time. Stereotactic Body Radiation Therapy (SBRT) is a technique that treats the prostate with fewer treatments and can decrease the effect of radiation to the surrounding tissues. This study is a Phase I research study, which means that it will look at the safety of the dose of the SBRT. While SBRT itself is a standard of care method to administer radiation therapy, there has not been a specific dose outlined in the past. The aim of this study is to determine the dose that will treat the prostate cancer but cause the least amount of side effects.

Inclusion Criteria:

• Willing and capable to provide informed consent
• Signed study specific informed consent
• Prostate specific-antigen (PSA) ≤ 10 Gleason 2-7
• Appropriate staging studies identifying as American Joint Committee on Cancer (AJCC) stage T1a, T1b, T1c, T2a, T2b
• No direct evidence of regional or distant metastases after appropriate staging studies
• Histologic confirmation of cancer by biopsy
• Age ≥ 18
• Karnofsky Performance Status must be ≥ 70
• American Urological Association (AUA) score must be ≤ 15 (alpha blockers allowed)

Exclusion Criteria:

• Female
• Positive lymph nodes of 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 non-melanomatous skin cancer are all permissable)
• T2c, T3, or T4 tumors
• Previous pelvic radiotherapy
• Previous surgery or chemotherapy for prostate cancer
• Previous transurethral resection of the prostate (TURP) or cryotherapy to the prostate
• Concomitant hormonal 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
• Severe, active co-morbidity defined as follows:
• Unstable angina and/or congestive heart failure requiring hospitalization within the last 6 months.
• Transmural myocardial infarction within the last 6 months
• Acute bacterial or fungal infection requiring intravenous antibiotics at the time of registration
• Chronic Obstructive Pulmonary Disease exacerbation or other respiratory illness requiring hospitalization or precluding study therapy within 30 days before registration
• Hepatic insufficiency resulting in clinical jaundice and/or coagulation defects; note, however, that laboratory tests for liver function and coagulation parameters are not required for entry into this protocol
• Acquired Immune Deficiency Syndrome (AIDS) based upon current Center Disease Control and Prevention (CDC) definition; note, however, that HIV testing is not required for entry into this protocol. The need to exclude patients with AIDS from this protocol is necessary because the treatments involved in this protocol may be significantly immunosuppressive. Protocol-specific requirements may also exclude immuno-compromised patients.
• History of treatment with potent immunosuppressive drugs for such conditions as post organ transplant, severe rheumatoid arthritis, etc. within the past 6 months.