Types of Uterine Cancer

Uterine cancer is a type of cancer which originates from the uterus, primarily from the uterine lining. It is one of the most common forms of cancer in women. There are 2 main types of uterine cancer, namely endometrial cancer/uterine lining cancer and uterine sarcoma. The classification of uterine cancer depends on which part of the uterus the cancer originates from — the uterine lining (endometrium) or the muscle and supporting tissues.

Knowing the type of uterine cancer you have will help you and your healthcare providers determine the appropriate treatment options. A biopsy is typically conducted to determine what subtype of uterine cancer you have. The type of uterine cancer is important in understanding how the cancer may behave, what kind of treatment(s) might be available to you, as well as the kind of benefit you might be able to expect from these treatments. All of these considerations play a role in determining the chances of the cancer going away and the chances of living a normal life expectancy.

Endometrial cancer, otherwise known as uterine lining cancer, arises from the inner lining of the uterus. This comprises the majority of uterine cancers, and accounts for approximately 90% of all uterine cancers. Endometrial cancer can be further classified based on the histology of the cancer cells (i.e., what they look like under the microscope). The most common histology is endometrioid carcinoma. It is typically less aggressive and associated with excessive estrogen exposure.

Endometrial cancer is usually treated by surgery (typically hysterectomy), radiation therapy, chemotherapy, hormone treatment, or some combination of the above. The treatment method depends on the stage of the cancer and the grade of the tumor.

Uterine sarcoma is a rarer and more aggressive form of uterine cancer. It accounts for approximately 3–7% of all uterine cancers. Uterine sarcoma originates from the deeper layers of the uterus, within the muscle or other supporting tissues. Uterine sarcomas are generally further classified based on the type of cell that the cancer originates from. Uterine leiomyosarcoma is the most common type of uterine sarcoma, characterized by a tumor starting in the smooth muscle layer (myometrium).

Similar to that of endometrial cancer, treatment for uterine sarcoma typically involves surgery, radiation therapy, chemotherapy and hormone therapy. However, treatment is usually done at higher frequencies due to the more aggressive nature of sarcomas relative to endometrial cancers.

Uterine carcinosarcoma, previously known as malignant mixed mullerian tumors, is another rare form of uterine cancer. It accounts for less than 5% of all uterine cancers. Uterine carcinosarcoma exhibits features of both endometrial carcinoma and sarcoma, manifesting itself as a mixture of two types of cancer cells. These tumors are now generally grouped with endometrial cancers, although their more aggressive behavior is recognized as distinctly different than most of the other endometrial carcinomas.

While there is no current treatment guideline for this type of cancer, surgery remains the primary form of treatment. Adjuvant therapy such as chemotherapy and radiation therapy is also employed.