Uterine cancer types

Uterine cancer, which forms in the uterus or womb, is the most common kind of cancer affecting the female reproductive system. According to the American Cancer Society (ACS), about 66,200 new uterine cancer cases are expected to be diagnosed in the United States in 2023, most commonly among women who have gone through menopause. On average, it’s most often diagnosed at age 60.

Uterine cancer has two primary types that develop in different parts of the uterus, as listed below.

Endometrial cancer: This type of cancer develops in the lining of the uterus, called the endometrium. It's the most common type of uterine cancer, accounting for more than 90 percent of cases.

Uterine sarcoma: A rarer type of uterine cancer, uterine sarcoma forms in the muscles or other tissues of the uterus.

Endometrial cancer

Endometrial cancer is the most common form of uterine cancer. Because the endometrium (the inner lining of the uterus) is part of the uterus, endometrial cancer is often referred to as uterine cancer. Endometrial cancer, sometimes described as cancer of the uterine lining, is the most commonly diagnosed gynecologic cancer (which includes cancers of the uterus, cervix, ovaries, vulva, vagina and fallopian tubes).

More than 80 percent of all endometrial cancers are adenocarcinomas of the endometrium. This type of cancer forms when cells in the endometrium begin to grow out of control. Endometroid carcinoma accounts for most cases of endometrial adenocarcinoma.

Other types of endometrial cancer include those listed below.

Serous adenocarcinoma: These tumors are more likely to spread to the lymph nodes and other parts of the body.

Adenosquamous carcinoma: This rare uterine cancer is similar to endometrial adenocarcinoma and carcinoma of the squamous cells that line the outer layer of the uterus.

Uterine carcinosarcoma: With this rare type of cancer, the cancer cells look like endometrial cancer and sarcoma. This type of cancer has a high risk of spreading to the lymph nodes and other parts of the body.

Primary pure squamous cell carcinoma of the endometrium: This very rare form of uterine cancer occurs so infrequently that only 70 cases have been diagnosed worldwide.

Uterine clear cell carcinoma: This rare type of endometrial cancer represents fewer than 5 percent of all uterine cancers.

Doctors classify the different types of endometrial cancer based on what the cells look like when examined under a microscope. Your care team will likely perform an endometrial biopsy to collect cells, which they can later observe up close to determine that classification.

Learn more about endometrial cancer survival rates

Uterine sarcoma

Uterine sarcomas, which form in the muscle wall of the uterus, make up less than 4 percent of all cancers of the uterus. Each subtype of uterine sarcoma differs in the way it develops and changes over time, as well as in how it’s treated. Doctors classify uterine sarcomas based on the type of cells in which the cancers begin. These include:

Uterine leiomyosarcoma, the most common type of uterine sarcoma, forms in the muscular wall of the uterus, known as the myometrium, and it makes up about 2 percent of uterine cancers.

Endometrial stromal sarcomas develop in the connective tissue that supports the endometrium. These cancers represent less than 1 percent of all uterine cancers, and typically grow slowly.

Undifferentiated sarcoma, a rare subtype, is similar to endometrial stromal sarcoma, but it’s more aggressive, meaning it grows and spreads more quickly. These cancers make up less than 1 percent of all uterine cancers.

Learn more about uterine sarcoma survival rates

If you’re interested in learning more about gynecologic cancer treatment, or if you want a second opinion about your diagnosis and treatment plan, call us or chat online with a member of our team. 

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