Types of Uterine Cancer

Cancers that begin in the uterus usually are one of these two types:

  • Endometrial cancer (or endometrial carcinoma) begins in the cells that make up the endometrium, the inner lining of the uterus. This is the most common type of uterine cancer and accounts for about 9 out of ten cases. Because endometrial cancer is often found before it spreads beyond the uterus, it can often be cured with proper treatment. Several subtypes of endometrial cancer exist:
    • endometrioid is by far the most common subtype
    • serous carcinoma
    • clear cell carcinoma
    • carcinosarcoma, also called malignant mixed Mullerian tumor (MMMT)

The latter three — serous carcinoma, clear cell carcinoma and MMMT — are rare, aggressive subtypes of endometrial cancer. They grow more quickly and are harder to treat than the endometrioid type, but Roswell Park’s team of gynecologic oncologists are experts at treating these rare cancer types, too.

Endometrial cancer staging

  • Uterine sarcoma begins in the muscular, middle layer of the uterus. This cancer type is less common and more difficult to treat than endometrial cancer. Uterine sarcoma is usually one of these subtypes:
    • uterine leiomyosarcoma (uLMS)
    • endometrial stromal sarcoma (ESS)
    • undifferentiated uterine sarcoma
  • Other, very rare types of uterine sarcoma include:
    • adenosarcoma
    • PEComas
    • rhabdomyosarcoma

Uterine sarcoma staging

Benign uterine tumors — fibroids

Many women develop tumors in the wall of the uterus that are benign, meaning they are not cancerous. You may have heard them referred to as “fibroids.” Medically speaking, they’re called leiomyomas. These tumors are more common as women age, especially in their 40s and 50s. As many as 20% to 80% of women develop fibroids by the age of 50. Because fibroids are not cancer, treatment is only necessary if they cause symptoms, such as pain, pelvic or rectal pressure, frequent urination and heavy menstrual bleeding.

If an apparent fibroid causes symptoms or looks suspicious on imaging, the only way to know whether the tumors are cancerous or not, is to undergo biopsy so that a pathologist may analyze samples of the cells.