Which of the following is protective against both endometrial and ovarian cancers?

• A. Unopposed estrogen therapy
• B. Combined oral contraceptives
• C. Tamoxifen therapy
• D. Late menopause

Answer: (B)

Together, protection against both endometrial and ovarian cancers comes from reducing estrogen-driven endometrial proliferation and cutting the number of ovulations. Combined oral contraceptives deliver progestin with estrogen; the progestin counteracts estrogen’s stimulatory effect on the endometrium, lowering endometrial cancer risk. At the same time, regular suppression of ovulation means fewer hormonal cycles and less repetitive damage to the ovarian surface, which lowers ovarian cancer risk. The longer you use them, the greater the protective effect, and some protection persists for years after stopping.

Unopposed estrogen therapy increases endometrial cancer risk because there’s no opposing progestin to counteract the estrogen’s proliferative effect on the uterine lining. Tamoxifen has estrogen-like effects on the endometrium, increasing endometrial cancer risk. Late menopause increases lifetime estrogen exposure and the number of ovulations, raising the risk rather than protecting against these cancers.