RATIONALE: Lycopene, a substance found in tomatoes, may lower prostate-specific antigen (PSA) levels and slow or prevent the development of prostate cancer.

PURPOSE: Phase II trial to study the effectiveness of lycopene in treating patients who have asymptomatic metastatic prostate cancer and a rising PSA level.

OBJECTIVES:

Primary

• Determine the percentage of patients with asymptomatic androgen-independent metastatic prostate cancer and an elevated prostate-specific antigen (PSA) level who sustain a decline in PSA after 4 months of treatment with lycopene.

Secondary

• Determine the response duration of PSA decline in patients treated with this therapy.
• Determine the time to the first consistent PSA increase in patients treated with this therapy.
• Determine whether a decline in PSA coincides with evidence of disease regression on physical examination or radiographic assessment in patients treated with this therapy.
• Determine the adverse event profile of this therapy in these patients.
• Determine the factors that motivate prostate cancer patients to enroll in a nutritional-based therapy study.

OUTLINE: This is a multicenter study.

Patients receive oral lycopene twice daily on days 1-28. Courses repeat every 28 days for at least 4 months in the absence of disease progression or unacceptable toxicity.

Patients are followed every 3 months until disease progression and then every 6 months for up to 5 years.

DISEASE CHARACTERISTICS:

• Diagnosis of androgen-independent prostate cancer

• Asymptomatic metastatic disease

  • Unlikely to become symptomatic within the next 4 months
  • No bone pain, shortness of breath, fatigue, or urinary symptoms directly attributable to prostate cancer

• Radiologic, physically palpable, and/or biochemical evidence of tumor progression after prior orchiectomy OR during treatment with a luteinizing hormone-releasing hormone (LHRH) agonist OR after initiation of another hormonal agent

• Sustained prostate-specific antigen (PSA) elevation, defined by the following:

  • PSA greater than 5 ng/mL
  • At least 2 consecutive increases in PSA at least 1 week apart
  • Sustained increase in PSA at least 4 weeks after discontinuation of prior flutamide (or other antiandrogen therapy) or megestrol AND at least 6 weeks after discontinuation of prior bicalutamide

• No known CNS metastases or carcinomatous meningitis

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-2

Life expectancy

• At least 12 weeks

Hematopoietic

• Not specified

Hepatic

• Bilirubin no greater than 1.5 mg/dL* NOTE: *Includes patients with liver involvement secondary to tumor

Renal

• See Disease Characteristics
• Creatinine no greater than 2 times upper limit of normal

Pulmonary

• See Disease Characteristics

Other

• No other malignancy within the past 5 years except basal cell skin cancer
• No medical or psychiatric condition that would preclude study participation

PRIOR CONCURRENT THERAPY:

Biologic therapy

• More than 4 weeks since prior immunotherapy

Chemotherapy

• More than 4 weeks since prior chemotherapy
• No concurrent chemotherapy

Endocrine therapy

• See Disease Characteristics
• More than 4 weeks since prior hormonal therapy (other than an LHRH agonist)
• No concurrent corticosteroids
• No concurrent progestational agents
• No concurrent new hormonal therapy

Radiotherapy

• No concurrent radiotherapy, including radiotherapy for new bone disease

Surgery

• See Disease Characteristics

Other

• More than 4 weeks since other prior anticancer therapy
• No other concurrent investigational anticancer agents
• No other concurrent alternative medicine therapies (e.g., saw palmetto or PC-SPES)