Internet based double-blind cross-over clinical trial to test efficacy of high dose isoflavone soy in controlling breast cancer survivor hot flashes

Abstract

636 Background: Severe hot flashes are common after completion of allopathic breast cancer treatment. Hot flashes are rare in the Orient where high isoflavone soy diets are common. Methods: We enrolled breast cancer survivors experiencing hot flashes after the completion of surgery, radiation and chemotherapy into a 16 week double blind cross-over casein placebo controlled trial of a 160 mg isoflavone soy dietary supplement. Hot flash frequency, severity, and time of day, exercise time and patient journaling was recorded by an internet diary placed on a HIPPA compliant server with password access. Results: Of 168 patients enrolled, 117 actually participated in taking supplementation and completing internet diaries giving adequate data for analysis. Of this group 13 patients dropped out of study for failure to finish all dietary supplements throughout the study period. The hot flash data during the last 4 weeks on each supplement was compared to determine benefit. There was no statistical difference in hot flash frequency, intensity or duration between either supplement independent of exercise level. Interestingly, 82% of patients reported a decrease in hot flashes in the first 4 weeks of study independent of which supplement they were randomized to receive. The journal entries report during this “induction” period that the majority of patients had identified emotional or dietary or other triggers for their hot flashes. The avoidance of the triggers seemed to substantially reduce their reported menopausal symptoms. Conclusions: High dose soy isoflavone dietary supplementation is ineffective in reducing breast cancer survivor hot flashes. Journaling may have a benefit in allowing survivors to find their individual triggers for the most severe hot flashes. Internet patient data entry provides a unique and highly compliant tool for obtaining direct patient reporting in survivorship clinical trials. [Table: see text]