Risk-Benefit Profiles of Women Using Tamoxifen for Chemoprevention


Risk-Benefit Profiles of Women Using Tamoxifen for Chemoprevention by Hazel B. Nichols, Lisa A. DeRoo, Daniel R. Scharf, Dale P. Sandler


Affiliations of authors

Department of Epidemiology, University of North Carolina Gillings School of Global Public Health, Chapel Hill, NC (HBN); Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway (LAD); Westat, Durham, NC (DS); Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC (DPS).

Study scope/scale

The Sister Study, a cohort of 50,884 US and Puerto Rican women age 35 to 74 years enrolled from 2003 to 2009.

Key outtakes

  • “Tamoxifen has been US Food and Drug Administration–approved for primary prevention of breast cancer since 1998 but has not been widely adopted, in part because of increased risk of serious side effects.”
  • “…20% of women who used tamoxifen had insufficient evidence that the benefits of tamoxifen outweigh the risk of serious side effects.”
  • “After 4.5 years, 46% of women had discontinued tamoxifen.”
  • “While the majority of women who used tamoxifen for primary prevention of breast cancer were likely to benefit, substantial discontinuation of tamoxifen before five years and use by women at risk of serious side effects may attenuate benefits for breast cancer prevention.”
  • “An estimated 15% of US women age 35 to 79 years are eligible for breast cancer chemoprevention; however, less than 5% may have favorable risk-benefit profiles.”
  • “National estimates indicate that less than 1% of eligible women use tamoxifen for prevention.”
  • “…substantial nonadherence to the recommended five-year course of tamoxifen has been reported in prevention trials.”
  • “…risk of serious side effects (endometrial cancer, stroke, pulmonary embolism, deep vein thrombosis, and cataract)…”
  • “At 4.5 years, 46% of tamoxifen users had discontinued use.”
  • “Tamoxifen users were 49% more likely (95% CI = 1.05 to 2.11) to report cataract…”
  • “Recent trials of aromatase inhibitors (23,24) show important benefits for breast cancer prevention; however, their use is limited to postmenopausal women. Until alternative therapies for premenopausal women become available, tamoxifen will continue to have an important role in breast cancer primary prevention.”
  • “…review of studies examining decision making surrounding tamoxifen use concluded that higher perceived breast cancer risk increased willingness to consider tamoxifen for prevention, but few other characteristics have been identified.”


The full paper can be found here: Click here