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.