Endometrial cancer forms in the tissue that lines the inside of the uterus. It is one of the most common cancers in American women. Most endometrial cancers start in cells that make mucus and other fluids. They are adenocarcinomas.
Endometrial cancer is one type of uterine cancer. Uterine cancer also can start in the cells that make up the wall of the uterus. These cells are muscle or myometrial cells. Cancers that start in these cells become sarcomas. They are much less common. When people say uterine cancer, they are often talking about endometrial cancer.
The cause of endometrial cancer is mostly unknown. The following factors may increase a woman’s risk of developing the disease. Many relate to having higher levels of estrogen.
- Age – The risk of endometrial cancer goes up as a woman gets older. The average age of diagnosis is 60. This cancer is rare in women under 45.
- Obesity or Being Overweight – This is a major risk factor. Women who have more fat tissue have more estrogen which increases risk.
- Diet – Eating a diet high in animal fat may increase risk.
- Prior Radiation Therapy – Radiation to the pelvic area can damage the DNA of cells. This can increase risk of this cancer including sarcomas.
- Hormone Use – Women who take unopposed estrogen without progesterone, especially for long periods of time, have a higher risk.
- Tamoxifen – Women who take this drug have a slightly higher risk of this cancer. Tamoxifen is also associated with a slight increased risk of developing uterine sarcomas. It is used to prevent or treat breast cancer.
- Menstrual Cycles – Women who have more periods may have a higher risk. This may result from early onset of menstruation (before age 12) or late onset menopause (after age 55). The risk comes from having more periods, so starting early and ending early or starting late and ending late may not increase risk. Having many pregnancies can help protect against this cancer.
- Polycystic Ovarian Syndrome (PCOS) – Women with PCOS have higher estrogen levels and lower levels of progesterone and may have a higher risk.
- Family history – This type of cancer appears to run in some families. Women with a family history of colon cancer and/or endometrial cancer should talk with a doctor about their risk.
- History of Cancer – Women who have had breast, colon, or ovarian cancer may have a higher risk of getting endometrial cancer.
- Diabetes – Having Type 2 diabetes can increase your risk. This may be in part because it is linked to obesity.
- Endometrial Hyperplasia – Cell growth can cause the uterus to thicken. This is not cancer but, in rare cases, it can increase the risk for cancer.
Signs & Symptoms
Endometrial or uterine cancer usually develops after menopause or around the time that menopause begins. Common symptoms include:
- Abnormal Bleeding – Abnormal vaginal bleeding or discharge is the most common symptom. You may notice watery, blood-streaked flow that gradually contains more blood.
- Abnormal Pain – Difficult or painful urination, pain during intercourse, or pain in the pelvic region
There is no routine screening for endometrial cancer. It is usually found after a woman notices symptoms.
Endometrial cancer is often found at an early stage. This is because it causes pain or unusual or heavy bleeding. These symptoms can have other causes as well. The following tests or exams may be used to see if cancer is present:
The doctor feels the pelvic area. They check the vagina, uterus, bladder, and rectum for lumps or changes in shape and size. They may insert a speculum into the vagina to see the upper part of the vagina and the cervix.
Sound waves and a computer are used to create a picture of the uterus. The picture can show tumors and abnormalities. If the endometrium looks too thick, the doctor will do a biopsy.
This test is used to detect cancer of the cervix. The doctor takes cells from the cervix and upper vagina. The cells are sent to a lab to be checked for abnormal cells. While it does not usually find uterine cancer, it may be used to rule out cervical cancer.
The doctor removes samples of tissue from the lining of the uterus. This is usually done in the doctor’s office, but in some cases, the patient needs a dilation and curettage (D & C). This is a same-day surgery. A pathologist then checks the samples for cancer cells.
Detailed pictures of areas inside the body are taken from different angles. A dye may be swallowed or injected into a vein to help the organs or tissues show up more clearly.
Radio waves and a strong magnet are used to get a detailed image. An MRI may be used to see how far cancer has grown into the uterus.
If cancer is diagnosed, the doctor needs to know the stage, or extent, of the disease to determine the best treatment. Staging is used to find out whether the cancer has spread, and if so, to which parts of the body. Staging is conferred based on findings at the time of surgery to treat the cancer. The pathologist may use a grading system (grades 1-3) to describe how the cells look under a microscope. Cells that look more like healthy cells have a lower grade. Pathologists will also assign the cancer a cell type, such as endometrioid (most common), clear cell, mucinous, or serous, for example.
- Stage I – The cancer is only in the body of the uterus. It is not in the cervix. Stage I has two levels depending on where the cancer is found.
- Stage II – The cancer has spread from the body of the uterus to the cervix.
- Stage III – The cancer has spread outside the uterus, but not outside the pelvis (and not to the bladder or rectum). It may have spread to the vagina, ovaries, or lymph nodes in the pelvis. Stage III has four levels depending on where the cancer is found.
- Stage IV – The cancer has spread into the bladder or rectum (stage IVA). Or, it has spread beyond the pelvis to other organs or body parts such as the lungs or bones (stage IVB).
When cancer spreads to the bone, it’s called “bone metastases.” This doesn’t mean you now have bone cancer—you still have the same type of cancer you started with.
Treatments & Side Effects
Treatment for endometrial cancer depends on the stage and where the cancer is found. If you still hope to get pregnant, talk with your doctor about your options before you start treatment. This will affect your treatment plan.
Most women have surgery. In some cases, it may be the only treatment needed. Radiation, hormone therapy, or chemotherapy may follow. When surgery is not an option, hormone therapy and radiation therapy are often used. If the cancer has spread, treatment may include targeted therapy or immunotherapy. Clinical trials may be an option as well.
Follow-up care after treatment is important. Even when there are no signs of disease, undetected cancer cells can remain in the body and cause the cancer to return. Your doctor will monitor your recovery and check for recurrence of the cancer. Checkups may include a physical exam, a pelvic exam, x-rays, and lab tests.
Treatment may include:
- Radiation Therapy
- Hormone Therapy
- Targeted Therapy
- Clinical Trials
Surgery is often used to treat uterine cancer. The surgery includes a total hysterectomy. This is an operation in which the uterus and cervix are removed. The surgery should be performed either laparoscopically or robotically, when deemed safe and appropriate by the surgeon. Often, the surgeon has to make a cut in the abdomen.
The operation also requires removal of the ovaries and fallopian tubes as well. This procedure is called a bilateral salpingo-oophorectomy. The doctor may also remove nearby lymph nodes to check for cancer. When the cancer is found early, surgery may be the only treatment used.
Common risks of surgery include pain, infection around the surgical site, tiredness, scarring, and numbness. A hysterectomy brings an end to menstrual periods. Women can no longer get pregnant. When the ovaries are removed in women who have not gone through menopause, menopause occurs at once. This may cause hot flashes and other symptoms. These symptoms may be more severe than those caused by natural menopause. The removal of lymph nodes can lead to swelling and pain. This condition, called lymphedema, can be long lasting.
Radiation therapy is the use of high-energy rays to kill or damage cancer cells.
Two types of radiation may be used to treat this cancer.
External radiation involves the use of a large machine. It is done on an outpatient basis. It does not take long, but you may need to go to hospital five days/week for a month or more.
Internal radiation therapy uses tiny tubes. The tubes contain a radioactive substance. They are inserted through the vagina and left in place for a few days. This treatment involves a hospital stay. A patient may not be allowed visitors to protect others from radiation exposure.
Some women have both external and internal radiation.
Besides the traditional side effects of radiation therapy, some women have dryness, itching, tightening, and burning in the vagina. Doctors may advise their patients not to have intercourse during radiation therapy.
Hormone therapy is the use of drugs that block hormones that drive cancer growth. In endometrial cancer, it often takes the form of progesterone in pill form. Other drugs may be an option too. Blood tests may help identify cancers that are more likely to respond to hormone therapy. It is used after or in place of surgery.
Common side effects include hot flashes, buildup of fluid, sleep problems, and muscle aches. Increased appetite may lead to weight gain. Women who are still menstruating may have changes in their periods.
Chemotherapy involves the use of drugs to destroy cancer cells. It is a systemic (whole body) treatment.
Chemotherapy may be used to treat high-grade endometrial cancers that can grow quickly. It is also used for stage III and IV cancers that return after treatment. Most patients receive chemotherapy after surgery, sometimes with radiation. It is given through a vein. Often, you will get a combination of two drugs.
Immunotherapy uses the body’s natural defenses (the immune system) to find, attack, and kill cancer cells.
Immunotherapy can be used in combination with targeted therapy for people with advanced endometrial cancer that tests negative to MSI-high or dMMR, after other treatment has been tried.
Targeted therapy aims to more precisely attack cancer cells. These drugs target changes in the genes or proteins of cancer cells that help them grow, divide, and spread.
Be sure to ask about clinical trials. Clinical trials are research studies to test new treatments or learn how to use current treatments better. Today’s standard drugs were once in clinical trials. Tomorrow’s drugs are in them today.
In some cases, the treatments with the best chance of success may be available only through clinical trials. Trials are offered for many cancers, at many different stages. Everyone is not eligible for every trial. If you have cancer that has come back or spread, it is especially important to ask about clinical trials.