Endometrial Cancer: A Plain-Language Overview

This page is for anyone who wants a clear overview of endometrial cancer. It covers risk factors, warning signs, diagnosis, cell types and molecular groups, staging, and treatment.

Endometrial cancer begins in the endometrium, the lining of the uterus. The American Cancer Society projects about 68,270 new cases of uterine cancer and 14,450 deaths in the United States for 2026, a figure SEER Stat Facts carries; NCI's PDQ summary still quotes the 2025 version. It is the most common gynecologic cancer here and makes up about 7% of all cancers in women.

Most of the risk traces to estrogen that is not balanced by progesterone. PDQ lists obesity and cycles without ovulation. It also lists estrogen-only hormone therapy after menopause. Tamoxifen, taken for breast cancer, is on the list too. Other risks include:

• diabetes
• metabolic syndrome
• never having given birth
• an early first period
• polycystic ovary syndrome
• Lynch syndrome, an inherited condition

PDQ calls irregular vaginal bleeding the most common presenting sign, and notes it usually appears early. That is the reason most people are diagnosed at a highly curable stage I, and NCI's screening summary says 85% of cases are found at a low stage.

The CDC says bleeding is never normal after your periods stop, and to see your doctor right away. The American Cancer Society says to report any vaginal bleeding, spotting or abnormal discharge after menopause. It also says to have a doctor check any irregular bleeding right away. Call your care team right away for any of these:

• any vaginal bleeding at all after menopause, even a single spot.
• bleeding between periods, or a change in your periods.
• any new bleeding while taking tamoxifen.
• bleeding that returns after a biopsy came back normal.

That last one matters more than people expect. PDQ notes that sampling error limits the meaning of a negative result. It cites a trial in which 36% of biopsies had too little tissue for a diagnosis. A normal result on a scanty sample is not the same as a normal endometrium.

Transvaginal ultrasound, or TVU, measures how thick the lining is. Among women with postmenopausal bleeding who turned out to have cancer, 96% had an endometrial thickness above 6 mm. In one study of women with postmenopausal bleeding, a 4 mm cutoff found 100% sensitivity (it caught every cancer) but only 60% specificity (many women without cancer also tested positive), and 46% of those women measured above 4 mm.

PDQ says there is no evidence that screening with ultrasound lowers deaths from endometrial cancer. It also says that using the same cutoff in women with no symptoms gives very high false-positive rates.

The diagnosis itself comes from tissue. Endometrial sampling in the office has largely replaced dilation and curettage as the first test. If sampling fails or the bleeding persists, hysteroscopy allows the uterus to be seen directly.

PDQ gives the distribution. Endometrioid carcinoma accounts for about 75%. Uterine papillary serous carcinoma is under 10% and carries a worse outlook. Clear cell carcinoma is about 4%, also with poorer outcomes. Carcinosarcoma is about 3%. It is now grouped as a gland cancer with sarcoma-like change, not as a sarcoma.

PDQ also describes an older split. Type 1 tumors are linked to unopposed estrogen. Type 2 tumors develop from thin, inactive (atrophic) endometrium and are not linked to hormones.

The Cancer Genome Atlas sorted these tumors into four molecular groups. PDQ says this testing is encouraged in every patient, where it is available.

• POLE ultramutated. PDQ says adjuvant therapy (extra treatment after surgery) is avoided in this group.
• MSI hypermutated, also called mismatch repair deficient or dMMR.
• Copy number low, also called no specific molecular profile or NSMP.
• Copy number high, also called p53 abnormal.

PDQ says these groups can be used to sort people into lower-risk and higher-risk categories. The results can change treatment. For example, FDA has approved immunotherapy with chemotherapy for advanced or recurrent disease, and mismatch repair status was used to sort people in the trials below.

Stage I is confined to the body of the uterus and the ovary. IA means disease limited to the endometrium, or a nonaggressive type invading less than half the muscle wall. IB means a nonaggressive type invading half or more. IC covers aggressive cell types still limited to the endometrium or a polyp.

Stage II reaches the deep tissue of the cervix. It also covers heavy lymphovascular space involvement, meaning tumor inside small vessels. IIA is cervical stromal invasion. IIB is substantial vessel involvement. IIC is an aggressive type with muscle wall involvement.

Stage III means spread near the uterus. IIIA reaches the outer surface, or the ovaries and tubes. IIIB reaches the vagina, or the tissue beside the uterus. IIIC reaches lymph nodes in the pelvis or beside the aorta.

Stage IV means invasion of bladder or bowel lining, or spread to distant sites.

For early endometrial cancer, PDQ describes the standard surgery as removal of the uterus and cervix along with the ovaries and tubes, done with a minimally invasive (laparoscopic) approach. PDQ says laparoscopy is favored because recovery is better, without a significant effect on outcomes.

Whether to check lymph nodes depends on measured risk. PDQ describes three groups. Grade 1 tumors held to the lining carry under 5% risk of node involvement. Grade 2 or 3 tumors that invade less than half the wall carry 5% to 9% pelvic node risk. Risk beside the aorta is about 4%. Deep, high-grade, or spread tumors carry 20% to 60% pelvic node risk. Risk beside the aorta runs 10% to 30%. PDQ says lymph node staging should be done for intermediate-high and high-risk disease. Ask your team which group you are in.

Sentinel lymph node biopsy finds the first node the tumor drains to and removes only that one. PDQ calls it an adequate alternative to full node removal for staging.

For stage I or II, grade 1 to 2 disease, PDQ lists surgery, vaginal brachytherapy (internal radiation) after surgery, or radiation alone.

For grade 3 disease, which includes serous, clear cell and carcinosarcoma, PDQ lists surgery followed by chemotherapy with or without radiation. For these cell types, PDQ describes carboplatin plus paclitaxel, based on small case series.

Two immunotherapy drugs are now FDA approved with chemotherapy for first treatment of advanced or recurrent disease.

FDA approved pembrolizumab with carboplatin and paclitaxel for advanced or recurrent disease. The trial was KEYNOTE-868/NRG-GY018, with 810 patients. Chemotherapy was paclitaxel and carboplatin for 6 cycles. Pembrolizumab was given during chemotherapy and then for up to 14 more cycles, for up to 24 months. Your team sets the doses. In the dMMR group, median time without the cancer growing was not reached. It was 6.5 months with placebo. The hazard ratio was 0.30. In the mismatch repair proficient group, it was 11.1 months against 8.5 months. The hazard ratio was 0.60.

FDA also approved dostarlimab-gxly with carboplatin and paclitaxel, based on the RUBY trial in 494 patients. Dostarlimab was given with chemotherapy and then alone for up to 3 years. Your team sets the doses. Median overall survival was 44.6 months against 28.2 months, a hazard ratio of 0.69. That approval no longer requires a dMMR or MSI-high result.

NCI lists three more approved drugs. They are durvalumab, lenvatinib, and megestrol acetate.

PDQ says that among women with Lynch syndrome (also called HNPCC), the estimated cumulative risk of endometrial cancer ranges from 20% to 60% by age 70. PDQ says some guidelines suggest a yearly ultrasound with endometrial biopsy for women aged 25 to 35. Ask your genetic counselor and care team what is right for you.

If your tumor is dMMR, ask whether that reflects an inherited change or one acquired by the tumor alone. The answer affects your relatives, not only you.

• Call 911 or go to the nearest emergency department if you have very heavy vaginal bleeding or other substantial bleeding, black or tarry stool, blood in vomit or vomit that looks like coffee grounds, or sudden confusion or being hard to wake.
• If you are having chemotherapy or immunotherapy, call your care team right away, day or night, for a temperature of 100.4°F (38°C) or higher, chills, sore throat, mouth sores, burning when you urinate, or any other sign of infection, even without a fever. A normal temperature is not a reason to wait.
• Call your care team right away if you have any vaginal bleeding after menopause, or new pelvic pain or pressure (CDC lists both as symptoms to report).

• https://www.cancer.gov/types/uterine/hp/endometrial-treatment-pdq
• https://www.cancer.gov/types/uterine/hp/endometrial-screening-pdq
• https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-pembrolizumab-chemotherapy-primary-advanced-or-recurrent-endometrial-carcinoma
• https://www.fda.gov/drugs/resources-information-approved-drugs/fda-expands-endometrial-cancer-indication-dostarlimab-gxly-chemotherapy
• https://www.cancer.gov/about-cancer/treatment/drugs/endometrial
• https://seer.cancer.gov/statfacts/html/corp.html
• https://www.cdc.gov/uterine-cancer/symptoms/index.html
• https://www.cancer.org/cancer/types/endometrial-cancer/detection-diagnosis-staging/signs-and-symptoms.html
• https://www.cancer.gov/about-cancer/treatment/side-effects/infection