Detection of a negative correlation between prescription of Chinese herbal products containing coumestrol, genistein or daidzein and risk of subsequent endometrial cancer among tamoxifen-treated female breast cancer survivors in Taiwan between 1998 and 2008: A population-based study.
ETHNOPHARMACOLOGICAL RELEVANCE
Tamoxifen users sometimes seek complementary and alternative medicine advice for treatment of a variety of illness and co-administer with phytoestrogen-containing herbs, resulting in an increasing concern of its influence in subsequent endometrial cancer risk. Our study aims to determine the prevalence of Chinese herbal products containing coumestrol, genistein, or daidzein and their association with subsequent endometrial cancer risk among tamoxifen-treated breast cancer survivors in Taiwan.


METHODS
We selected all patients who were newly diagnosed with invasive breast cancer and received tamoxifen treatment between January 1, 1998, and December 31, 2008, from the National Health Insurance Research Database. Among the 26,656 tamoxifen-treated breast cancer survivors, we evaluated the usage, frequency of service, and prescription of Chinese herbal products containing coumestrol, genistein, or daidzein. The logistic regression method was employed to calculate the odds ratios for utilization of those herbal products. Cox proportional hazard regression was set to calculate the hazard ratios of endometrial cancer associated with such usage.


RESULTS
Of the patients surveyed, 36.2% (n=9652) of the tamoxifen-treated breast cancer survivors examined in the study had consumed Chinese herbal products containing coumestrol, genistein, or daidzein during the study period. Exposure to Ge Gen(Puerariae Radix) specifically was the most extensive. For it, the population consumed an average cumulative dose of above 180g. Compared to those who had never used Chinese herbal products, breast cancer survivors who had taken Chinese herbal products containing coumestrol, genistein, or daidzein concurrently with tamoxifen treatment did not have a higher hazard ratio for subsequent development of endometrial cancer.


CONCLUSION
Among those tamoxifen-treated female breast cancer survivors in Taiwan, consumption of Chinese herbal products containing coumestrol, genistein, or daidzein is negatively correlated with subsequent endometrial cancer risk.
['Hu|Yi-Cheng|YC|', 'Wu|Chien-Tung|CT|', 'Lai|Jung-Nien|JN|', 'Tsai|Yueh-Ting|YT|']
D000328:Adult D000368:Aged D001943:Breast Neoplasms D016022:Case-Control Studies D003375:Coumestrol D004365:Drugs, Chinese Herbal D016889:Endometrial Neoplasms D005260:Female D019833:Genistein D006801:Humans D007529:Isoflavones D008875:Middle Aged D017741:Survivors D013624:Taiwan D013629:Tamoxifen D055815:Young Adult
Chinese herbal product Coumestrol Genistein Daidzein Breast cancer Tamoxifen National health insurance research database Herb-drug interaction Phytoestrogen