Recuritment Challenges

Right now it is not possible to predict which patients are going to react more to RT. Many things could affect patient's response to radiation. One of the factors is whether the person can repair damage to the genetic material (DNA/RNA) caused by the RT. There is some evidence that a certain protein called Gamma H2AX is involved in DNA damage and repair and this can be used to predict the sensitivity of individual patients. The investigators will be studying this protein: Gamma H2AX) in the blood samples of prostate cancer patients exposed to both computed tomography (CT) scan and RT treatment. This will help us to understand why different individuals show differences in side effects following RT.

Inclusion Criteria:

• Intermediate-risk prostate cancer patients (T1/T2N0M0 with either GS < 7 and PSA between 10-20 ng/ml or GS 7 and PSA less than 20 ng/ml).
• Planned for radical RT to the prostate with IMRT planning (79Gy/39fractions or 60 Gy/20 fractions).
• No contraindications to diagnostic CT scanning.
• Prostate volumes will be less than 80 cc to control the planning dose volume histogram (DVH) as much as possible in terms of rectal and bladder volumes.
• No known DNA repair disorders (e.g. family history of AT, BRCA1/2 or Li Fraumeni syndrome) or contraindications to radical pelvic RT.

Exclusion Criteria:

• Inability to provide informed consent.
• Patient having contraindications to diagnostic CT scan.
• Patients who have unobtainable data regarding previous therapy and their clinical outcome.
• Patients should not have any diagnostic X-rays or CAT scans 2 weeks prior to their enrollment into the study.

Patients with intermediate-risk prostate cancer