Bortezomib With or Without Hormone Therapy in Treating Patients With Relapsed Prostate Cancer

DISEASE CHARACTERISTICS: * Histologically confirmed adenocarcinoma of the prostate * Relapsed disease after definitive local therapy, as documented only by a rise in prostate-specific antigen (PSA) * Experienced PSA relapse after definitive local therapy * Rising PSA (≥ 1.0 ng/mL after nadir \< 1.0 ng/mL) * PSA increase of ≥ 0.3 ng/mL (increase occurred between 2 separate measurements taken ≥ 4 weeks apart) * The first of these two PSA values must rise above a previously recorded post-therapy nadir value * Ineligible for curative therapy * No clinical evidence of local recurrence (i.e., palpable induration or mass in the prostatic fossa) other than PSA elevation * No evidence of palpable disease in the prostatic bed * No metastatic disease (M0) * No non-nodal (\> N1) metastasis * No evidence of osseous metastasis on bone scan within the past 28 days PATIENT CHARACTERISTICS: Age * Over 18 Performance status * ECOG 0-1 Life expectancy * At least 1 year Hematopoietic * Platelet count ≥ 30,000/mm\^3 * Absolute neutrophil count ≥ 1,000/mm\^3 Hepatic * No known hepatitis B or C positivity Renal * Creatinine clearance ≥ 30 mL/min Immunologic * No known human T-cell lymphotropic virus positivity * No hypersensitivity to bortezomib, boron, or mannitol * No known HIV 1 or 2 positivity * No active, ongoing bacterial, viral, or fungal infection Other * Fertile patients must use effective contraception * No peripheral neuropathy ≥ grade 2 * No other disease, condition, or social or geographic constraint that would preclude study participation * No other malignancy within the past 5 years except basal cell or squamous cell skin cancer PRIOR CONCURRENT THERAPY: Biologic therapy * Not specified Chemotherapy * No concurrent chemotherapy Endocrine therapy * See Disease Characteristics * At least 6 months since prior hormonal therapy combined with radiation therapy as definitive therapy * Neoadjuvant hormonal therapy prior to definitive therapy (e.g., surgery, radiation therapy, brachytherapy, or cryoablation) allowed * No other concurrent hormonal therapy Radiotherapy * See Disease Characteristics * More than 12 months since prior radioactive seed therapy * No concurrent radiotherapy Surgery * See Disease Characteristics * More than 4 weeks since prior surgery * No concurrent surgery Other * No concurrent second-line herbal preparations, including PC-SPES * No other concurrent investigational agents