title: The use of Chinese herbal products and its influence on tamoxifen induced endometrial cancer risk among female breast cancer patients: a population-based study.
abstract: BACKGROUND
  The increased practice of traditional Chinese medicine (TCM) worldwide has raised concerns regarding herb-drug interactions. The purpose of our study was to analyze the use of Chinese herbal products (CHPs) and to estimate the influence of the use of CHP on tamoxifen induced endometrial cancer risk among female breast cancer patients in Taiwan.
  
  
  METHODS
  All patients newly diagnosed with invasive breast cancer receiving tamoxifen treatment from January 1, 1998 to December 31, 2008 were selected from the National Health Insurance Research Database. The usage, frequency of service, and CHPs prescribed among the 20,466 tamoxifen-treated female breast cancer patients were analyzed. The logistic regression method was employed to estimate the odds ratios (ORs) for utilization of CHPs. Cox proportional hazard regression was performed to calculate the hazard ratios (HRs) for subsequent endometrial cancer for CHP non-users and CHP users among female breast cancer patients who had undergone tamoxifen treatment.
  
  
  RESULTS
  More than half of the subjects had ever used a CHP. Jia-Wei-Xiao-Yao-San (Augmented Rambling Powder) and Shu-Jing-Huo-Xue-Tang (Channel-Coursing Blood-Quickening Decoction) were the two most commonly used CHPs. The HR for the development of endometrial cancer among CHP users was 0.50-fold (95% CI=0.38-0.64) compared to that of CHP non-users.
  
  
  CONCLUSIONS
  More than half of the study subjects had ever used a CHP. Jia-Wei-Xiao-Yao-San was the most commonly used CHP. Among female breast cancer patients who had undergone tamoxifen therapy, CHP consumption decreased the risk of subsequent endometrial cancer. Exploring potential Chinese herb-tamoxifen interactions and integrating both healthcare approaches are beneficial to the overall health outcomes of tamoxifen-treated female breast cancer patients.
authors.affiliation: Institute of Traditional Medicine, School of Medicine, National Yang-Ming University, No.155, Sec. 2, Li-Nong Road, Taipei 112, Taiwan; Department of Chinese Medicine, Taipei City Hospital, Yangming Branch, Taipei, Taiwan. Electronic address: yuehting.tsai@gmail.com.
authors.forename: Yueh-Ting
authors.initials: YT
authors.lastname: Tsai
authors.affiliation: Institute of Traditional Medicine, School of Medicine, National Yang-Ming University, No.155, Sec. 2, Li-Nong Road, Taipei 112, Taiwan; Department of Chinese Medicine, Taipei City Hospital, Yangming Branch, Taipei, Taiwan; Taiwan Association for Traditional Chinese Medicine of Family, Taiwan. Electronic address: kareny@ms10.hinet.net.
authors.forename: Jung-Nien
authors.initials: JN
authors.lastname: Lai
authors.affiliation: Institute of Traditional Medicine, School of Medicine, National Yang-Ming University, No.155, Sec. 2, Li-Nong Road, Taipei 112, Taiwan; Taiwan Association for Traditional Chinese Medicine of Family, Taiwan. Electronic address: nealwu@gmail.com.
authors.forename: Chien-Tung
authors.initials: CT
authors.lastname: Wu
mesh_terms: D000328:Adult; D000368:Aged; D018931:Antineoplastic Agents, Hormonal / Q000009:adverse effects*; D001943:Breast Neoplasms / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D016208:Databases, Factual; D004365:Drugs, Chinese Herbal / Q000009:adverse effects*; D016889:Endometrial Neoplasms / Q000139:chemically induced* / Q000175:diagnosis / Q000453:epidemiology / Q000517:prevention & control; D005260:Female; D041743:Herb-Drug Interactions; D006801:Humans; D016015:Logistic Models; D008516:Medicine, Chinese Traditional; D008875:Middle Aged; D016017:Odds Ratio; D008517:Phytotherapy; D010946:Plants, Medicinal; D016016:Proportional Hazards Models; D065840:Protective Factors; D018570:Risk Assessment; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology; D013629:Tamoxifen / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D018931:Antineoplastic Agents, Hormonal; D004365:Drugs, Chinese Herbal; D013629:Tamoxifen
keywords: Breast cancer; Chinese herbal product; Herb–drug interaction; National Health Insurance Research Database; Tamoxifen