Endometrial cancer and menopausal hormone therapy in the National Institutes of Health-AARP Diet and Health Study cohort

Cancer. 2007 Apr 1;109(7):1303-11. doi: 10.1002/cncr.22525.


Background: Menopausal hormone therapy formulations for women without hysterectomy have included estrogen plus progestin for years, but endometrial cancer risks associated with the use of sequential and continuous estrogen-plus-progestin regimens remain unclear.

Methods: The National Institutes of Health-AARP Diet and Health Study included 73,211 women who were ages 50 years to 71 years at baseline and who completed 2 questionnaires (1995-1996 and 1996-1997). Linkage to state cancer registries and mortality indices identified 433 incident endometrial cancers through 2000. Using proportional hazards regression, the authors estimated relative risks (RRs) and 95% confidence intervals (95% CIs) relative to never-use of hormone therapy.

Results: In 51,312 women who never used hormones or only used estrogen-plus-progestin regimens at doses consistent with current practice, neither sequential estrogen plus progestin (daily estrogen plus progestin for 10-14 days per cycle: RR, 0.74; 95% CI, 0.39-1.40) nor continuous estrogen plus progestin (daily estrogen plus progestin for >/=20 days per cycle: RR, 0.80; 95% CI, 0.55-1.15) had any statistically significant association with endometrial cancer. Long durations (>/=5 years) of sequential regimen use (RR, 0.79; 95% CI, 0.38-1.66) and of continuous regimen use (RR, 0.85; 95% CI, 0.53-1.36) were not associated with endometrial cancer.

Conclusions: Confirmation that these estrogen-plus-progestin regimens neither increase nor decrease the risk of endometrial cancer could influence menopausal symptom management for women who are considering estrogen-plus-progestin therapy.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Aged
  • Cohort Studies
  • Diet
  • Endometrial Neoplasms / epidemiology*
  • Estrogen Replacement Therapy*
  • Estrogens / administration & dosage*
  • Female
  • Humans
  • Incidence
  • Middle Aged
  • Postmenopause*
  • Progestins / administration & dosage*
  • Prospective Studies
  • Registries
  • Risk Assessment
  • Risk Factors
  • Surveys and Questionnaires
  • United States / epidemiology
  • Women's Health


  • Estrogens
  • Progestins