Efficacy of keishibukuryogan for hot flashes in prostate cancer patients receiving androgen deprivation therapy: a sub-analysis focusing on hormonal and cytokine levels

BACKGROUND: The current study attempted to elucidate the mechanisms of keishibukuryogan (TJ-25) efficacy by focusing on hormonal and cytokine levels. This is a sub-analysis of serum hormonal and cytokine levels extracted from the single-arm prospective study. METHODS: Twenty-five participants were administrated TJ-25 at a dose of 2.5 g three times daily for 12 weeks, and competed for a diary of their hot flashes conditions. Various hormonal and cytokine values, including interleukin (IL)-8 and tumor necrosis factor-α (TNF-α), were measured at the baseline and 12-week visits. The correlation of hot flashes with hormonal and cytokine levels at baseline was investigated. As part of the responder analyses, all participants were divided into two groups based on the median baseline values of all hormones and cytokines at baseline, and the change amounts in strength and frequency of hot flashes from baseline to 12-week visits in both groups were compared. Furthermore, a correlation in change amounts (Δ values) by TJ-25 administration between hot flashes and each parameter was also conducted. RESULTS: Hot flashes intensity was inversely related to estradiol levels (r=−0.433, P=0.019), and frequency was inversely related to progesterone levels (r=−0.415, P=0.025). In the responder analyses, the effectiveness of TJ-25 for hot flash strength increased in the patients with higher levels of TNF-α at baseline (P=0.0372). TJ-25 was more efficient in frequency in the patients with higher levels of IL-8 (P=0.0312). TJ-25 efficacy, on the other hand, was not significantly associated with changes in any hormonal or cytokine levels between the baseline and 12-week visits. However, ΔIL-8 and ΔTNF-α were not significantly correlated with Δstrength and Δfrequency of hot flashes by TJ-25 administration. CONCLUSIONS: Hot flashes were inversely correlated with estradiol and progesterone levels. TJ-25 was more effective in patients with higher TNF-α and IL-8 levels, with no significant change in serum levels caused by the treatment. The suggestive mechanism for the effects of keishibukuryogan is that this drug doesn’t suppress the production of IL-8 and TNF-α, but may inhibit some actions of these cytokines.