DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed adenocarcinoma of the prostate

• Rising prostate-specific antigen (PSA) (absolute PSA value > 2.0 ng/mL above the nadir) after a nadir (< 4 ng/mL for post-radiotherapy patients and 0.3 ng/mL for post-prostatectomy patients) after local curative therapy (radical prostatectomy and/or pelvic irradiation)

  • Confirmed by 2 sequential PSA increases of at least 0.5 ng/mL each, taken ≥ 2 weeks apart
  • Absolute increase in PSA must be ≥ 2 ng/mL in patients who received prior radiotherapy
• PSA ≥ 2 ng/mL

• No clinical or radiographic evidence of metastatic or locally recurrent disease

  • CT scan or MRI of the chest/abdomen/pelvis AND bone scan negative for metastatic disease within the past 4 weeks

PATIENT CHARACTERISTICS:

Age

• Not specified

Performance status

• ECOG 0-2

Life expectancy

• More than 3 months

Hematopoietic

• Absolute neutrophil count ≥ 1,000/mm^3
• Platelet count ≥ 100,000/mm^3 (transfusion independent, defined as no transfusion within the past 3 weeks)
• Hemoglobin ≥ 8.0 g/dL (transfusion or exogenous epoetin alfa allowed)

Hepatic

• Bilirubin ≤ 1.5 mg/dL
• AST and ALT < 2.5 times upper limit of normal

Renal

• Creatinine ≤ 1.5 g/dL OR
• Creatinine clearance or radioisotope glomerular filtration rate ≥ 50 mL/min

Cardiovascular

• No symptomatic congestive heart failure
• No unstable angina pectoris
• No cardiac arrhythmia

Other

• Fertile patients must use effective contraception during and for at least 3 months after study participation
• Able to swallow entire intact capsules
• No prior allergic reaction attributed to compounds of similar chemical or biological composition to study drug (i.e., retinoids)
• No CNS toxicity > grade 3

• No uncontrolled seizure disorder

  • Seizure disorders are allowed provided patient is on anticonvulsants and disorder is well controlled
• No other concurrent uncontrolled illness
• No ongoing or active infection
• No psychiatric illness or social situation that would preclude study compliance
• No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer, carcinoma in situ, or adequately treated stage I or II cancer currently in complete remission
• No known retinopathy

• No known uncontrolled hypertriglyceridemia resulting in pancreatitis

  • Triglycerides < 300 mg/dL

PRIOR CONCURRENT THERAPY:

Biologic therapy

• No prior or concurrent biological response modifiers for recurrent prostate cancer

Chemotherapy

• No prior cytotoxic chemotherapy
• No prior chemotherapy for recurrent prostate cancer
• No other concurrent anticancer chemotherapy

Endocrine therapy

• Prior neoadjuvant or adjuvant hormone ablation therapy allowed provided it was administered in conjunction with primary definitive therapy ≤ 9 months in duration
• No prior androgen ablative therapy
• No prior or concurrent corticosteroids for recurrent prostate cancer
• No prior or concurrent hormonal therapy for recurrent prostate cancer
• At least 1 year since prior androgen deprivation
• No concurrent tamoxifen
• No concurrent hormone ablative agents (including steroids)

Radiotherapy

• See Disease Characteristics
• Prior adjuvant radiotherapy for positive margins or pT3 disease allowed
• Prior radiotherapy allowed for local recurrence provided the patient has had a subsequent rise in PSA level from a nadir of < 4 ng/mL
• No concurrent radiotherapy for persistent PSA or for local recurrence
• No concurrent radiotherapy for recurrent prostate cancer

Surgery

• See Disease Characteristics

Other

• No more than 1 prior investigational anticancer agent
• No concurrent complementary or alternative therapy (e.g., Hypericum perforatum [St. John's wort], PC-SPES, or any other herbal remedies) for prostate cancer
• No concurrent combination antiretroviral therapy for HIV-positive patients
• No concurrent drugs suspected of causing pseudotumor cerebri (e.g., tetracycline, nalidixic acid, nitrofurantoin, phenytoin, sulfonamides, lithium, amiodarone, or vitamin A)
• No concurrent drugs that modulate intracellular ceramide levels, ceramide cytotoxicity, sphingolipid transport, or p-glycoprotein or multidrug resistance-associated protein-1 drug/lipid transporters (e.g., cyclosporine, verapamil, ketoconazole, chlorpromazine, mifepristone, indomethacin, or sulfinpyrazone)
• No concurrent antioxidant supplements (e.g., ascorbic acid or vitamin E)
• No concurrent participation in another therapeutic clinical trial