The effect of the duration of progestin use on the occurrence of endometrial cancer in postmenopausal women.
OBJECTIVE
Women who have ever used estrogen replacement therapy (ERT), even at a low dose, have an increased incidence of endometrial cancer. The addition of a progestin to ERT reduces the incidence of endometrial cancer. The duration of progestin administration is more important than the dose.


METHODS
A MEDLINE review of the literature was performed using the search terms endometrial cancer, epidemiology, and hormone replacement therapy (HRT).


RESULTS
Women who have ever used ERT have an increased incidence of endometrial cancer. The use of HRT for more than 5 years, with a progestin use of <10 days per cycle, has a relative risk = 1.8. Continuous combined HRT, or sequential or cyclic HRT with >10 days of progestin per cycle, appears to decrease the incidence of endometrial cancer to that found in nonusers of HRT.


CONCLUSIONS
The use of HRT in postmenopausal women with a uterus reduces the incidence of endometrial cancer. The duration of progestin administration should be 14 days or more per cycle based on recent epidemiologic data.
Archer
D F
DF
Department of Obstetrics and Gynecology, and Clinical Research Center, Eastern Virginia Medical School, Norfolk, Virginia, USA. archerdf@evms.edu
D016022:Case-Control Studies; D015331:Cohort Studies; D016889:Endometrial Neoplasms / Q000139:chemically induced* / Q000453:epidemiology / Q000517:prevention & control*; D015914:Estrogen Replacement Therapy / Q000009:adverse effects* / Q000379:methods*; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D017698:Postmenopause / Q000187:drug effects* / Q000502:physiology; D011372:Progestins / Q000627:therapeutic use*; D012307:Risk Factors; D013997:Time Factors
D011372:Progestins