Protection Against Endometrial Cancer, Contraception
Dr. Álvaro Monterrosa Castro, MD
Histological types of endometrial carcinoma
There are several histological types of endometrial carcinoma, of which the most common is adenocarcinoma. In 1980, it was estimated that 149,000 new cases of endometrial carcinoma occurred in the world.
The incidence rate of neoplasia increases after forty years of age, with risk factors being considered: obesity, hyperglycemia, high blood pressure, chronic anovulation, polycystic ovary syndrome, nulliparity, early menarche and late menopause (81).
A relationship has been observed between endometrial cancer and the endogenous estrogen stimulus, when there is an inadequate cyclical exposure of progesterone, likewise that exogenous estrogens increase the risk of endometrial cancer in postmenopausal women treated with estrogens without the cyclical administration of progestin, girls with dysgenesis ovarian diseases treated during puberty with only estrogens and women who received sequential oral contraceptives, where the pharmacological preparation included many tablets with only estrogens (81).
A group of experts gathered in 1992 by the World Health Organization reviewed 11 case-control studies and 3 cohort studies, observing a protective effect of combined oral contraceptives against endometrial cancer.
The Cancer and Hormones Study (CASH) (95) showed that just one year of use of combined oral contraceptives reduced the risk of endometrial cancer by half and the protective effect remained for at least 15 years. They assert that both high-dose and reduced-dose pills have a protective effect.
(Read Also: Protection Against Benign Breast Tumors)
Protective effect
Some evidence shows that the protective effect emerges quite soon after the start of the method (99).
Another pooled analysis of data from several case-control and cohort studies (100) showed a significant trend toward decreased risk of endometrial cancer with longer duration of combined oral contraceptive use.
The risk reduction was estimated as follows: at one year 23%, at two years 38%, at four years 51%, at eight years 64% and at twelve years 70%.
Combined oral contraceptives reduce the risk of endometrial cancer (82,94), this is confirmed in the meta-analysis by Schlesselman (101) published in 1997, which included ten case-control studies and one cohort study, where they also A 50% reduction in risk was found.
Protection is slightly reduced to 67% after five years of suspension in use, and to 40% after twenty years of suspension. This protection of combined oral contraceptives is against three major histological types of endometrial cancer: adenocarcinoma, adenoacanthoma and adenosquamous.
Jensen and Sperof (43) comment that the multicenter case-control study from the United States, where a 60% risk reduction was observed, shows that the protective effect on the endometrium initially observed in macrodose pills continues to be present with the 30 and 35 ug pills of ethinyl estradiol. The use of combined oral contraceptives is associated with a low risk of endometrial cancer (10).
Estimated relative risk of endometrial cancer in users of combined oral contraceptives
The following table presents a list of the most important studies where the estimated relative risk of endometrial cancer in users of combined oral contraceptives has been estimated, compared to women who had never used the pill.
Dr. Álvaro Monterrosa Castro, MD
Leave a Comment