The uterus is a pear-shaped organ located in the pelvis of people assigned female at birth. This is where a baby grows during pregnancy. There are more than 66,000 new cases of uterine cancer diagnosed every year—predominantly endometrial cancer—making it the most common gynecologic cancer in the US. About 13,000 people die from these cancers every year.
The highest rates of uterine cancer are seen in post-menopausal people, predominantly those who are white. Individuals who experience abnormal vaginal bleeding, especially if it occurs after menopause, are encouraged to see their doctor, as this is a predominant symptom of uterine cancer.
What Is It?
Uterine cancer is a gynecologic cancer that develops when abnormal cells grow out of control in the inner lining of the uterus (endometrium) or uterine muscle. Estimates suggest that 90-95% of uterine cancers are endometrial cancer, with the remainder being uterine sarcoma.The success of treatment and survival rate depend on the stage uterine cancer is diagnosed and its type. For endometrial cancer that is localized, the five-year survival rate is 95%; it's 69% when it's regional (meaning it has spread to nearby tissues or lymph nodes. In general, uterine sarcoma is a more aggressive form of cancer and is, unfortunately, commonly diagnosed in more advanced stages. The five-year survival rates for localized and regional uterine sarcoma are 66% and 34%, respectively. Each cancer becomes more difficult to treat when it has spread to distant organs and tissues in the body, lowering the survival rate.
There are two primary types of uterine cancer: endometrial cancer and uterine sarcoma.
Most uterine cancer starts in the cells of the inner lining of the uterus, which is called the endometrium. (Endometrial cells shed during menstruation.) Endometrial cancer is the most common cancer of the female reproductive organs in the US. While there are many subtypes of endometrial cancer, two of the most frequently diagnosed are endometrioid adenocarcinoma and uterine carcinosarcoma.
This type of uterine cancer is considered rare, as it makes up just about 5-10% of cases of uterine cancer. The most frequently seen subtype of this cancer is called a uterine leiomyosarcoma, which is cancer that begins in the uterine muscle (the myometrium, which pushes a baby out during birth). Uterine sarcoma can also start in the connective tissue (stroma), but it's less common. This cancer is more aggressive and challenging to treat compared to endometrial cancer.
One of the most important things to pay attention to are your periods. If your flow changes, especially if it becomes heavier or you notice spotting, you'll want to see your doctor. After menopause, it's not normal to experience vaginal bleeding.
The cause of uterine cancer isn't known, but it's most likely related to a disrupted hormonal imbalance in the body that leads to higher levels of estrogen. Overtime, this can lead to abnormal growth of the lining of the uterus.
Doctors suspect there are several risk factors for endometrial cancer and uterine sarcoma, though these things do not guarantee you will develop a cancer:
- Hormonal imbalance where there's increased estrogen levels in the body
- Type 2 diabetes
- High-fat diet
- Sedentary lifestyle
- Family or personal history of endometrial or colorectal cancer (also may be called Lynch syndrome)
- Personal history of breast or ovarian cancer
- Having ovarian tumors
- Early menstruation (before age 12)
- Late menopause (the average age of menopause is 51)
- Never having children or infertility (pregnancy is believed to be protective)
- Treatment with tamoxifen for breast cancer
- Radiation therapy for pelvic cancer (This is a specific risk factor for uterine sarcoma.)
- Prior diagnosis of polycystic ovary syndrome (PCOS)
- Prior diagnosis of atypical endometrial hyperplasia (a precancer of the endometrium)
There are no screening tests to pinpoint uterine cancer before signs and symptoms appear. If, after a physical exam and health history discussing symptoms, your doctor thinks you may be at risk for uterine cancer, you are experiencing symptoms, or they'd like to rule out cancer, then you may receive the following tests:
Endometrial biopsy: Your doctor removes tissue from the endometrium; this tissue will then be examined to spot cancer cells.
Dilatation and curettage (D&C): During this procedure, your doctor removes tissue from the lining of the uterus.
Hysteroscopy: This device helps doctors view the uterus to look for abnormalities. During this test, doctors may also be able to remove polyps or masses that are found.
Transvaginal ultrasound: The doctor inserts a probe into your vagina. The ultrasound creates sound waves that become images of your uterus.
Imaging tests: Other imaging tests, such as MRI, PET, or CT scans may be used to determine if the cancer has spread and to what body parts.
Treatment for uterine cancer depends on whether you were diagnosed with endometrial cancer or uterine sarcoma, as well as the stage of cancer, how far it's spread, and if you're eligible for a clinical trial. Often, a combination of therapies will be recommended.
- Surgery: Surgical options includes a total hysterectomy where the uterus, cervix, fallopian tubes, and ovaries are removed.
- Radiation therapy: High-energy x-rays are specifically directed at cancer cells. The type of radiation used may be external or internal.
- Chemotherapy: This treatment uses drugs, most frequently given intravenously, to kill cancer cells or stop the growth of cancer.
- Hormone therapy: Testing may reveal that you have a type of cancer where cells have specific hormone receptors, which means that there may be certain therapies that target these receptors.
- Targeted therapy: Targeted therapies block certain proteins or signals to single out specific cancer cells. This includes monoclonal antibody therapy, mTOR inhibitor therapy, and signal transduction inhibitor therapy.
Unfortunately, there are no screenings to detect an early cancer. As for uterine sarcoma, there are no steps you can take to prevent this cancer. However, there are a few healthy lifestyle habits you can pursue in order to decrease the likelihood of developing endometrial cancer:
Maintain a healthy weight: Estrogen is made and stored in fat tissue, and increased estrogen increases the risk for endometrial cancer. If your weight is considered in the overweight or obese category, talk to your doctor about healthy habits that can help you lose weight.
Exercise: Building physical activity into every day helps maintain a healthy weight, regulates blood pressure, and guards against diabetes, all risk factors for this cancer.
Take hormonal birth control: Women who take hormonal birth control pills long term are more protected from endometrial cancer, even after stopping the medication.
Take progesterone in certain circumstances: If you're taking estrogen therapy to treat the symptoms of menopause, your doctor will talk to you about taking progestins, as well, which can help counter this effect. This is called combination therapy, and comes with its own potential side effects, like increased risk of breast cancer and blood clots.
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