Definition

, the most common cancer of the female reproductive tract, occurs when abnormal cells form in the tissues of the uterus. It starts in the uterus and spreads through the blood and lymph systems. Cancers that occur in each part of the uterus have their own names, such as cervical cancer or endometrial cancer, but are sometimes broadly defined as uterine cancer because the structure is part of the uterus.

The most common type of cancer of the uterus begins in the endometrium (lining of the uterus). The second type of cancer seen in the uterus is uterine sarcoma. This type of cancer of the uterus occurs in the muscle.

Types of

There are many different types of uterine cancer. Each type varies in the way it behaves and how it should be managed.

For this reason, we often ask our specialists in pathology to review findings.

Endometrioid adenocarcinoma: This type of uterine cancer forms in the glandular cells of the uterine lining. It accounts for as much as 75 percent of all uterine cancers. Endometrioid adenocarcinoma is commonly detected early and has a high cure rate.

Serous adenocarcinoma: These tumors are more likely to spread to lymph nodes and other parts of the body. About 10 percent of uterine cancers diagnosed are of this type.

Adenosquamous carcinoma: This rare form of uterine cancer has elements of both adenocarcinoma and carcinoma of the squamous cells that line the outer surface of the uterus.

Carcinomasarcoma: This rare form of uterine cancer was previously thought to be a type of uterine sarcoma. However, it is now felt to be a uterine (endometrial) cancer.

It has elements of both adenocarcinoma and sarcoma. These tumors have a high risk of spreading to the lymph nodes and other parts of the body.

Uterine cancer risk factors

Anything that increases your chance of getting uterine cancer is a risk factor. These include:

Obesity: Being overweight raises your risk two to four times. A higher level of fat tissue increases your level of estrogen.

Eating a diet high in fat

Age: More than 95% of uterine cancers occur in women 40 and older.

Tamoxifen: This breast cancer drug can cause the uterine lining to grow. If you take tamoxifen and have changes in your menstrual period or bleeding after menopause, it is important to let your doctor know.

Estrogen replacement therapy (ERT) without progesterone if you have a uterus: Birth control pills may lower your risk.

Personal/family history of uterine, ovarian, or colon cancer: This may be a sign of Lynch syndrome (hereditary non-polyposis colorectal cancer or HNPCC). Learn more about hereditary cancer syndromes.

Ovarian diseases, such as polycystic ovarian syndrome (PCOS)

Complex atypical endometrial hyperplasia: This precancerous condition may become uterine cancer if not treated.

Simple hyperplasia rarely becomes cancer.

Diabetes

Never having been pregnant

The number of menstrual cycles (periods): If you started having periods before 12 years old or went through menopause late, your risk of uterine cancer may be higher.

Breast or ovarian cancer

Pelvic radiation to treat other kinds of cancer: The main risk factor for uterine sarcoma is a history of high-dose radiation therapy in the pelvic area.

Not everyone with risk factors gets uterine cancer: However, if you have risk factors, it's a good idea to discuss them with your doctor.

Causes of

The cause of uterine cancer is not known, but excess estrogen seems to increase the risk.

During a woman's reproductive years, the uterine lining, or endometrium, is in a continual cycle of growth and maturation. Estrogen encourages the growth of the endometrium, while progesterone encourages maturation.

When pregnancy does not occur, the resulting decrease in progesterone levels causes endometrial shedding and menstruation. High estrogen levels can lead to excessive growth (hyperplasia) of the endometrium, which can develop into cancer.

Uterine cancer occasionally runs in families, and individuals who have syndromes that increase the general risk of cancer may develop endometrial cancer.

Stages of uterine cancer

The stage provides a common way of describing cancer, enabling doctors to work together to plan the best treatments. Doctors assign the stage of endometrial cancer using the FIGO system.

Stage I: The cancer is found only in the uterus or womb, and it has not spread to other parts of the body.

Stage IA: The cancer is found only in the endometrium or less than one-half of the myometrium.

Stage IB: The tumor has spread to one-half or more of the myometrium.

Stage II: The tumor has spread from the uterus to the cervical stroma but not to other parts of the body.

Stage III: Cancer has spread beyond the uterus, but it is still only in the pelvic area.

Stage IIIA: Cancer has spread to the serosa of the uterus and/or the tissue of the fallopian tubes and ovaries but not to other parts of the body.

Stage IIIB: The tumor has spread to the vagina or next to the uterus.

Stage IIIC1: Cancer has spread to the regional pelvic lymph nodes.

Stage IIIC2: Cancer has spread to the para-aortic lymph nodes with or without spread to the regional pelvic lymph nodes.

Stage IV: Cancer has metastasized to the rectum, bladder, and/or distant organs.

Stage IVA: Cancer has spread to the mucosa of the rectum or bladder.

Stage IVB: Cancer has spread to lymph nodes in the groin area, and/or it has spread to distant organs, such as the bones or lungs.