The uterus has two layers: an outer muscle layer (called the myometrium) and a thin lining inside (called the endometrium) that sheds each month during a woman’s period or that thickens to support a baby as it grows during pregnancy. The lower part of the uterus is called the cervix; it keeps a baby inside the uterus until it stretches during labor to allow the baby to pass through.
Sometimes the endometrium becomes thickened. This is called endometrial hyperplasia. Most of the time, endometrial hyperplasia occurs when there is an imbalance of the female hormones estrogen and progesterone. When too much estrogen is present, it stimulates the lining of the uterus to grow and become abnormal. Risk factors for endometrial hyperplasia include being overweight, diabetes mellitus, polycystic ovarian syndrome, and taking estrogen supplements without progesterone.
Endometrial hyperplasia is a pre-cancerous condition. It usually develops in a stepwise progression over several years from simple thickening of the uterine lining (a very early pre-cancer) to the formation of glands in the thickened area to cellular changes in the abnormal glands. Left untreated, it can become a cancer. Women with hyperplasia often have bleeding and have a biopsy of the lining of the uterus. The pathologist looks at the tissue under a microscope to see how abnormal the cells are and how they have arranged themselves.
Simple endometrial hyperplasia is a thickening of normal cells of the uterine lining. It may cause abnormal bleeding, but needs limited treatment. It rarely becomes a cancer.
As the lining becomes more abnormal, the cells arrange to form glands that are very crowded in the tissue. Called complex hyperplasia, this is still an early form of pre-cancer, but further along than simple hyperplasia. If the tissue becomes more abnormal, the cells in the thickened tissue begin to change. The pathologist grades how abnormal the cells are (mild, moderate or severe). Severely atypical endometrial hyperplasia is the most advanced pre-cancer of the uterus.
When severely atypical hyperplasia is present, there is a 25-40% chance that a cancer is also present, but hasn’t been found yet. When moderate atypia or mild atypia are present, there is a significantly lower probability of an underlying cancer.
The treatment for endometrial hyperplasia depends on your age, whether you want to have children in the future, your medical history, and how atypical the cells are.
Patients who do not want more children.
For patients who are no longer able or do not want more children, a hysterectomy is one option. Certainly, for more severe pre-cancers (moderate or severely atypical), a hysterectomy (removal of the uterus and cervix) is the best treatment unless you are at unusually high risk for surgery. For most patients, surgery can be done robotically with a few small incisions and a quick return to normal activity. Because women with severe atypia may have an undiagnosed endometrial cancer, we usually do surgery as if there was a cancer present so that you would not need another surgery if cancer should be found.
An alternative to surgery for some patients is hormonal therapy. By giving the female hormone progestin, we can sometimes reverse the thickening effects of estrogen. Patients who are treated with hormones instead of surgery need to be watched carefully to make sure the pre-cancer gets better rather than worse. We do this by ordering ultrasounds of the uterus and biopsying the uterus every 3-4 months. Endometrial biopsies are done in the office and can be uncomfortable. In choosing hormone therapy instead of surgery, it is important to decide if you are able to tolerate frequent biopsies and ultrasounds. For a woman who can tolerate biopsies and would like to avoid surgery, hormonal therapy is an option for endometrial hyperplasia without atypia or with mild to moderate atypia.
Women under 40.
For those patients who want more children, a hysterectomy is generally not the preferred treatment. Instead, treatment may include a dilation and curettage (D&C) in the operating room. In this procedure, the cervix is stretched (dilation) and the lining of the uterus is scraped thoroughly and removed (curettage). Then the female hormone progestin is given (called progestational therapy) which can reverse the process of developing a severe atypia and cancer.
After about three months of treatment with progestin, your physician will order another ultrasound and endometrial biopsy. Endometrial biopsies are done in the office and can be uncomfortable. If the ultrasound and biopsy of the uterus still show pre-cancer, we can sometimes repeat the D&C and use higher doses of the hormone or other medications. In other cases, surgery may be needed. If the hyperplasia is completely gone, then options for further therapy may include birth control pills or some combination of hormones with progestational agents. If you wish to become pregnant, your physician will discuss the best timing and give directions about stopping hormones or birth control pills. At this time, you will return to your obstetrician/gynecologist (OB/Gyn) with occasional visits to your gynecologic oncologist.