RATIONALE: Gabapentin may be effective in relieving hot flashes in men who have prostate cancer. It is not yet known which regimen of gabapentin is most effective in treating hot flashes.

PURPOSE: Randomized phase III trial to compare different regimens of gabapentin in treating men who have prostate cancer.

OBJECTIVES:

• Determine the effectiveness of gabapentin in managing hot flashes in men with prostate cancer.
• Determine the response of patients to this drug.
• Determine the toxicity of this drug in these patients.
• Determine the quality of life of patients treated with this drug.

OUTLINE: This is a randomized, double-blind, placebo-controlled, multicenter study. Patients are stratified according to the number of hot flashes per day (2-3 vs 4-9 vs 10 or more) and duration of hot flash symptoms (less than 9 months vs 9 months or more). Patients are randomized to one of four treatment arms.

All patients are observed for 7 days prior to drug administration in order to collect baseline hot flash information.

• Arm I: Patients receive oral gabapentin once daily on days 1-28.
• Arm II: Patients receive oral gabapentin once daily on days 1-7 and twice daily on days 8-28.
• Arm III: Patients receive oral gabapentin once daily on days 1-7, twice daily on days 8-14, and three times daily on days 15-28.
• Arm IV: Patients receive oral placebo on one of three schedules corresponding to arms I-III.

Patients in all arms may continue therapy with gabapentin for an additional 8 weeks.

Quality of life is assessed at baseline, day 28, and at the end of the additional 8 weeks.

Patients are followed at 6, 12, and 24 months.

PROJECTED ACCRUAL: A total of 220 patients (55 per treatment arm) will be accrued for this study within 1 year.

• Hot Flashes
• Prostate Cancer

DISEASE CHARACTERISTICS:

• Diagnosis of prostate cancer
• Received or are currently receiving androgen ablation therapy

• Hot flashes for at least 1 month

  • At least 14 times per week and severe enough to require therapeutic intervention

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• ECOG 0-1

Life expectancy:

• At least 6 months

Hematopoietic:

• Not specified

Hepatic:

• Not specified

Renal:

• Creatinine < 1.5 times upper limit of normal over the past 2 years

Other:

• No prior allergic or adverse reaction to gabapentin

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• At least 4 weeks since prior antineoplastic chemotherapy
• No concurrent antineoplastic chemotherapy

Endocrine therapy:

• See Disease Characteristics
• At least 4 weeks since prior androgens, estrogens, or progestational agents
• No concurrent androgens, estrogens, or progestational agents
• Concurrent hormonal therapy allowed if on stable dose for at least 4 weeks and plan to continue therapy throughout study

Radiotherapy:

• Not specified

Surgery:

• Not specified

Other:

• No prior gabapentin
• No other concurrent treatment for hot flashes
• Concurrent antidepressants allowed if on stable dose for at least 1 month and plan to continue therapy throughout study