A preliminary report of a double blind placebo controlled trial of gabapentin for control of hot flashes in women with breast cancer. A University of Rochester Cancer Center CCOP study

Abstract

8017 Background: Hot flashes are experienced by a majority of women receiving systemic therapy for breast cancer. While estrogen replacement therapy can ameliorate these symptoms, controversy surrounds the use of estrogens in women with breast cancer. Based on initial observations by Thomas Guttuso (Neurology 2000;54:2161), and our pilot study (Breast Cancer Research and Treatment, in press), we conducted a double blind placebo controlled trial of gabapentin. Methods: Between June 2001 and July 2003, a total of 420 women with breast cancer on systemic therapy and having ≥2 hot flashes per day, were randomized from 18 participating CCOPs to placebo (P) or gabapentin (G) 100 mg or 300 mg po tid for 8 weeks. A self reported 1 week hot flash and other symptom inventory was kept by the patient prior to the start of treatment and during weeks 4 and 8 of the treatment. Results: Preliminary data are available on 360 women at week 4: P = 115, G100 = 123, G300 = 122 and 324 women at week 8: P = 103, G100 = 104, G300 = 117. All hot flashes were assigned a grade of 1, 2, 3 or 4 for mild, moderate, severe and very severe, respectively. A severity score was calculated by summation for each day (e.g., a woman who had 3 moderate hot flashes and 2 severe ones would have a severity score of 12 for that day). Neither mean hot flash severity nor mean frequency of hot flashes varied significantly at baseline. Analysis of Variance (ANOVA) at week 4 and at week 8 showed significant overall differences and significant linear trends in severity score and frequency of hot flashes, all ps≤0.005 (week 4 severity score: P=14.4, G100=12.2, G300=8.9; frequency: P=6.9, G100=5.9, G300=4.8, and week 8 severity score: P=13.4, G100=11.5, G300=8.6; frequency: P=6.7, G100=5.5, G300=4.6). This translates to a percent decrease in hot flash severity score from baseline as follows: week 4: P=23.3, G100=34.2, G300=48.1; week 8 P=18.0, G100=30.0, G300=45.6. Conclusions: This preliminary analysis suggests that gabapentin 300 mg po tid is effective in the control of hot flashes in women being treated for breast cancer. Supported by grant U10CA 37420 No significant financial relationships to disclose.