Also called uterine cancer, cancer of the endometrium, endometrial adenocarcinoma · Reviewed
Definition:Endometrial cancer is cancer that forms in the tissue lining the uterus, the endometrium. The NCI says most are adenocarcinomas, cancers that begin in cells that make and release mucus and other fluids. It is the first risk named in the boxed warning on estrogen labels.
The link to estrogen
Estrogen labels say a woman with a uterus who takes estrogen without a progestin, called unopposed estrogen, has a higher risk. The NCI describes endometrial hyperplasia as an overgrowth of the lining whose types differ in how likely they are to become cancer, and the labels call it a possible precursor.
Climara label: risk with estrogen alone about 2 to 12 times that of non-users, 15 to 24 times with 5 to 10 years or more of use, and lasting 8 to 15 years after stopping.
Premarin label, 1-year trial: endometrial hyperplasia 5% on 0.625 mg against 0% on placebo.
Prempro and Premphase list endometrial cancer in their boxed warning too.
What the labels say about bleeding
The labels say undiagnosed, persistent or recurring abnormal genital bleeding after menopause is checked, including with endometrial sampling when indicated. Undiagnosed abnormal bleeding is also listed as a reason not to start estrogen, as on the Climara label.
Why it matters for your log
Bleeding is what the labels ask doctors to check. A dated note of any bleeding, with what you were taking that week, makes the pattern easy to share.
General education drawn from labels and published studies, not personal medical advice. Your prescriber, pharmacist and the label that came with your product are the final word.
Why do estrogen labels warn about endometrial cancer?+
They say estrogen taken without a progestin by a woman with a uterus raises the risk, and that adding a progestin lowers the risk of endometrial hyperplasia, a possible precursor.
Is endometrial cancer the same as uterine cancer?+
The NCI defines endometrial cancer as cancer of the tissue lining the uterus. It is the most familiar kind of uterine cancer, but not the only one.