DISEASE CHARACTERISTICS:

• Histologically confirmed adenocarcinoma of the prostate
• Underwent prior radical prostatectomy as local definitive therapy for prostate cancer

• Meets criteria for 1 of the following strata:

  • Has received ≥ 9 months of androgen blockade therapy (either single-agent luteinizing hormone-releasing hormone or combined androgen blockade) for serologic progression after surgery

    • Serologic progression defined as a rising prostate-specific antigen, which has risen serially on two determinations (from baseline) ≥ 1 week apart, and no objective evidence of metastatic disease
    • Prior radiotherapy for serologic progression allowed
  • Did not receive any form of androgen blockade therapy within the past 9 months
• No metastatic disease by abdominal/pelvic CT scan and whole-body scan

PATIENT CHARACTERISTICS:

• Able to tolerate CT scanning in the supine position
• No prior medical condition known to have effects on the thymus, including myasthenia gravis, lymphoma, hyperthyroidism, or cachexia
• No autoimmune disorders
• No acute illness, including active infection requiring antibiotics

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• No prior systemic chemotherapy
• No prior immunological therapy
• No prior single-agent antiandrogen (e.g., high-dose bicalutamide)
• No prior or concurrent 5-alpha reductase inhibitors (e.g., finasteride), PC-SPES, or estrogen-containing nutraceuticals
• No concurrent systemic steroid therapy (topical steroids allowed)