Changes in DNA After Radiation Therapy in Patients With Prostate Cancer

Investigating Markers of Radiation Outcome in Patients With Intermediate-Risk Prostate Cancer Using DNA Microarray Analysis: An RTOG Pilot Study

RATIONALE: Collecting and storing samples of tissue from patients with cancer to study in the laboratory may help doctors learn more about changes that may occur in DNA after radiation therapy and identify biomarkers related to cancer.

PURPOSE: This laboratory study is looking at changes in DNA after radiation therapy in patients with prostate cancer.

OBJECTIVES:

Primary

• Demonstrate the feasibility of acquiring specimens, both frozen and paraffin-embedded, to yield RNA of adequate quality to perform DNA microarray studies on markers of radiotherapy outcome in patients with intermediate-risk prostate cancer.

Secondary

• Compare the gene expression results from frozen tissue and paraffin-embedded tissue to see the correlation between the 2 methods in patients treated on the brachytherapy alone arm of protocol RTOG-0232.
• Find genes that are expressed differentially before and after radiation therapy in patients treated on the brachytherapy plus external-beam radiation therapy arm of protocol RTOG-0232.
• Find gene expression patterns in patients treated on either arm of protocol RTOG-0232 who have significant associations with biochemically as well as clinically apparent local and distant failure.

OUTLINE: This is a multicenter, pilot study.

Frozen and paraffin-embedded tissue samples are studied for biomarker/laboratory analysis. DNA microarray analysis is performed on the samples to assess markers of radiotherapy outcome.

PROJECTED ACCRUAL: A total of 156 patients will be accrued for this study.

Inclusion Criteria:

• Histologically confirmed, locally confined adenocarcinoma of the prostate
• Zubrod performance 0-1
• Clinical stages T1c - T2b, N0, M0
• Combined Gleason score 7 if prostate specific antigen (PSA) < 10, combined Gleason score < 7 if PSA 10 - 20; PSA must be ≤ 20 ng/mL, before hormone therapy, if given, and a prostate volume by transrectal ultrasound (TRUS) ≤ 60 cc.
• American Urological Association (AUA) score ≤ 15 (alpha blockers are allowed).
• Age ≥ 18 years old and must sign a study-specific informed consent form

Exclusion Criteria:

• No clinically or pathologically involved lymph nodes
• No distant metastases or significant obstructive symptoms
• No prior chemotherapy, pelvic radiation, transurethral prostatectomy (TURP), cryosurgery, TUNA, transurethral microwave thermotherapy (TUMT) or radical surgery for carcinoma of the prostate is allowed.
• No previous hormonal therapy beginning < 2 months or > 6 months prior to registration is allowed.
• No previous or concurrent cancers other than basal, in situ, or squamous cell skin cancers unless the patient is disease free for ≥ 5 years.
• No hip prosthesis or major medical or psychiatric illnesses are allowed. prior to study entry.