Endometrial cancer starts in the lining of the uterus

Endometrial cancer begins in the endometrium, the tissue that lines the inside of the uterus. The cancer develops when cells in this lining grow abnormally and multiply without control. Most endometrial cancers are adenocarcinomas, meaning they start in the glandular cells of the endometrium.

The uterus is a hollow, pear-shaped organ where a fetus grows during pregnancy. The endometrium thickens and sheds each month during the menstrual cycle. When cells in this lining become cancerous, they can invade deeper into the uterine wall or spread to other parts of the body. Endometrial cancer is the most common cancer of the female reproductive system in the United States.

Key Takeaways

  • Endometrial cancer develops in the tissue lining the inside of the uterus and is usually diagnosed at an earlier stage than other cancers because abnormal bleeding is often an early warning sign.
  • Excess estrogen without enough progesterone is the most common cause, which is why obesity, diabetes, and certain hormone therapies increase risk.
  • Abnormal vaginal bleeding—especially after menopause—is the most common symptom and should be reported to a doctor.
  • Diagnosis involves a biopsy, where a small sample of endometrial tissue is removed and examined under a microscope.
  • Treatment options include surgery, radiation, chemotherapy, or hormone therapy, depending on how far the cancer has spread and other patient factors.

How endometrial cancer develops and spreads

Endometrial cancer typically develops over time as cells accumulate genetic changes. The cancer usually starts in one location within the endometrium and can grow into the muscle layer of the uterus (the myometrium). If not caught early, cancer cells can spread beyond the uterus to the cervix, fallopian tubes, ovaries, or other organs in the pelvis and abdomen.

The stage of the cancer—how far it has spread—determines treatment options and outlook. Stage 1 cancer is confined to the uterus. Stage 2 has spread to the cervix. Stage 3 has spread to the pelvis or lymph nodes. Stage 4 has spread to the bladder, bowel, or distant organs like the lungs or liver. Most endometrial cancers are caught at stage 1 or 2 because bleeding alerts women to see a doctor early.

Risk factors that increase the chance of developing endometrial cancer

The strongest risk factor for endometrial cancer is excess estrogen without enough progesterone. Estrogen stimulates the endometrium to grow and thicken. Progesterone normally balances this by telling cells to stop dividing. When estrogen is high and progesterone is low, cells can grow abnormally.

Obesity is the most common modifiable risk factor because fat tissue produces estrogen. Diabetes and high blood pressure also increase risk. Certain hormone therapies—specifically estrogen-only hormone replacement therapy taken without progesterone—raise risk significantly. Tamoxifen, a drug used to treat breast cancer, can increase endometrial cancer risk as a side effect. Age matters too: most cases occur in women over 50, though younger women can develop it. A personal or family history of Lynch syndrome (a hereditary condition affecting DNA repair) substantially increases risk.

Symptoms that may signal endometrial cancer

Abnormal vaginal bleeding is the most common symptom and often the first sign. This includes bleeding or spotting after menopause, bleeding between periods, or periods that are heavier or last longer than usual. Any postmenopausal bleeding should be reported to a doctor, even if it seems minor.

Other symptoms can include pelvic pain or pressure, pain during intercourse, or vaginal discharge that is watery or blood-tinged. These symptoms are not specific to cancer—they can result from many conditions—but they warrant medical evaluation. Because endometrial cancer often causes bleeding early on, it is frequently caught before it spreads widely.

How endometrial cancer is diagnosed

A doctor typically begins with a pelvic exam and may order a transvaginal ultrasound, where a small probe is inserted into the vagina to create images of the uterus. If the endometrium appears thickened or abnormal, or if symptoms persist, a biopsy is performed.

A biopsy is the only way to confirm endometrial cancer. During the procedure, a thin tube is inserted through the cervix into the uterus, and a small sample of endometrial tissue is removed. The sample is examined under a microscope to look for cancer cells. The biopsy can usually be done in an office setting without general anesthesia, though some discomfort is normal. Once cancer is confirmed, imaging tests like CT scans or MRI may be ordered to determine whether the cancer has spread beyond the uterus.

Treatment options for endometrial cancer

Surgery is the primary treatment for most endometrial cancers. The standard procedure is a hysterectomy—removal of the uterus—often combined with removal of the cervix, fallopian tubes, and ovaries. This surgery can usually be performed using minimally invasive techniques (laparoscopy or robotic surgery) rather than open surgery, which means smaller incisions and faster recovery.

After surgery, additional treatment may be recommended based on the stage and grade of the cancer. Radiation therapy uses high-energy beams to kill remaining cancer cells and is often used if the cancer has spread beyond the uterus or has high-risk features. Chemotherapy uses drugs to kill cancer cells throughout the body and may be given before or after surgery. Hormone therapy, using progestin (a synthetic form of progesterone), can slow or stop the growth of some endometrial cancers, particularly those that are hormone-sensitive. The specific combination of treatments depends on individual factors including age, overall health, and how advanced the cancer is.

Survival rates and long-term outlook

Endometrial cancer has a relatively favorable outlook compared to many other cancers, largely because it often causes symptoms early. The five-year survival rate—the percentage of people alive five years after diagnosis—varies by stage. For stage 1 cancer confined to the uterus, the five-year survival rate is approximately 95 percent. For stage 2, it drops to around 76 percent. For stage 3, it is roughly 60 percent, and for stage 4, approximately 17 percent.

These are population averages and individual outcomes vary based on age, overall health, tumor characteristics, and response to treatment. Many women treated for early-stage endometrial cancer live long, healthy lives after treatment. Regular follow-up appointments with an oncologist are important to monitor for recurrence and manage any long-term side effects from surgery, radiation, or chemotherapy.

Frequently Asked Questions

Can endometrial cancer be prevented?

There is no may provide way to prevent it, but you can reduce risk by maintaining a healthy weight, managing diabetes and high blood pressure, and discussing hormone therapy options with your doctor. If you take tamoxifen for breast cancer, your doctor should monitor you closely for endometrial changes. Women with Lynch syndrome should discuss screening options with their doctor.

Is endometrial cancer hereditary?

Most cases are not hereditary, but Lynch syndrome—an inherited condition affecting DNA repair—significantly increases risk. If you have a family history of endometrial, colon, or ovarian cancer, ask your doctor whether genetic testing might be appropriate for your situation.

What does a biopsy feel like?

Most women describe cramping or pressure during the procedure, similar to a strong menstrual cramp. It usually lasts only a few minutes. Some spotting or light bleeding afterward is normal. Over-the-counter pain medication taken before the procedure can help manage discomfort.

Will I need a hysterectomy even if the cancer is caught very early?

Hysterectomy is standard treatment for endometrial cancer at any stage because it removes the primary source of cancer and allows the surgeon to check whether cancer has spread to nearby lymph nodes. In rare cases of very early, low-grade cancers in young women who want to preserve fertility, doctors may discuss alternative approaches, but this is uncommon.