The 2 Main Types of Uterine Cancer, Explained

Uterine cancer is pretty much exactly what it sounds like—it's any type of cancer that starts in the uterus (the hollow, pear-shaped organ where fetuses grow). Upwards of 66,500 cases are diagnosed in the US in a year, making up about 3.5% of all new cancer cases, according to the National Cancer Institute (NCI).

Uterine cancer is the most common cancer of the female reproductive system, according to the NCI. But not all uterine cancer is the same. There are different types of uterine cancer, and which type a patient has can really impact their prognosis and treatment options.

Here, we break down the types of uterine cancer, explaining what the types mean as well as common symptoms and treatment options for each. Keep scrolling for everything you need to know.

Endometrial Cancer

Endometrial cancer, also called endometrial carcinoma, per the NCI, is the most common type of uterine cancer.

"The vast majority of uterine cancers are endometrial cancers," says Alison Schram, MD, attending physician in the early drug development and gynecologic medical oncology services at Memorial Sloan Kettering Cancer Center.

When you have this disease, cancerous cells form in the tissues of the endometrium (the inner lining of the uterus), explains the NCI. Endometrial cancer typically occurs after menopause; the average age of diagnosis is 60, reports the American Cancer Society (ACS).

Endometrial cancer can be divided into categories based on how the cells look under the microscope. These categories, per ACS, include:

Adenocarcinoma. Most endometrial cancers are adenocarcinomas, and the most common type of adenocarcinoma is endometrioid cancer. About 75 to 80% of endometrial cancers are endometrioid, Pamela Soliman, MD, professor and deputy chair of Gynecologic Oncology and Reproductive Medicine at the University of Texas MD Anderson Cancer Center, tells Health.

Endometrioid cancer starts in gland cells and looks a lot like normal uterine lining, reports ACS. Less common types of endometrial adenocarcinomas include: clear-cell carcinoma, mucinous adenocarcinoma, undifferentiated carcinoma, dedifferentiated carcinoma, and serous adenocarcinoma, per ACS. These types tend to grow and spread faster than most types of endometrial cancer. Oftentimes, they spread outside the uterus before they are diagnosed.

Uterine carcinosarcoma (CS). This is a type of endometrial cancer that starts in the endometrium and has features of both endometrial cancer and uterine sarcoma (a type of cancer that starts in muscle cells of the uterus), according to ACS.

Other, more rare types of endometrial cancer include:

• Squamous cell carcinoma
• Small cell carcinoma
• Transitional carcinoma
• Serous carcinoma

Signs and symptoms of endometrial cancer, according to the NCI, include:

• Vaginal bleeding or discharge not related to menstruation (periods).
• Vaginal bleeding after menopause.
• Difficult or painful urination.
• Pain during sexual intercourse.
• Pain in the pelvic area

Standard treatment options for endometrial cancer, according to the NCI, include surgery to remove the cancer, radiation therapy, chemotherapy, hormone therapy, and targeted therapy. Surgery is the most common treatment option for endometrial cancer, reports the NCI, but treatment is not one-size-fits-all. Factors including the specific type of endometrial cancer and how far it has spread in the body (among other things) can influence which treatment a patient receives, notes ACS.

Uterine Sarcoma

Uterine sarcoma is a rare type of uterine cancer that forms in muscle or other tissues of the uterus. Up to 10% of uterine cancers are sarcomas, reports ACS. This disease typically occurs after menopause.

Most uterine sarcomas are put into categories based on the type of cell where the cancer starts, according to ACS. These categories include:

• Uterine leiomyosarcoma (LMS): Cancer that starts in the muscular wall of the uterus (the myometrium). By far the most common type of uterine sarcoma, this cancer can grow and spread quickly.

• Endometrial stromal sarcoma (ESS): Cancer that starts in the supporting connective tissue (stroma) of the lining of the uterus. A rare cancer, ESS can grow slowly or quickly.

• Undifferentiated sarcoma: Cancer that starts in the lining of the uterus or in the muscular wall of the uterus. It grows and spreads quickly and tends to have a poor outlook.

Signs and symptoms of uterine sarcomas, according to the NCI, include:

• Bleeding that is not part of menstrual periods.
• Bleeding after menopause.
• A mass in the vagina.
• Pain or a feeling of fullness in the stomach.
• Frequent urination.

Treatment options for uterine sarcomas, according to the NCI, include surgery, radiation therapy, chemotherapy, and hormone therapy. As with endometrial cancer, treatment for uterine sarcoma is not one-size-fits-all. Factors including the specific type of uterine sarcoma and how far it has spread in the body (among other things) can influence which treatment a patient receives.