The uterus is a female reproductive organ with two main parts. The body of the uterus is hollow, and is where a fetus develops during pregnancy. The cervix is the lower portion of the uterus, and joins the organ to the vagina.
Uterine cancer is rare before the age of 45; the average age at diagnosis is 60. In the past decade, rates of uterine cancer have been climbing by about 1% annually in white women and 2-3% annually in all other racial and ethnic groups. It has also become more deadly over time; since 2000, the death rate from uterine cancer has risen by ~1.7% annually. About 3% of women (or people assigned female at birth) will be diagnosed with some form of uterine cancer during their lives.[1]
Uterine cancer can cause a range of symptoms, including:
Abnormal vaginal bleeding (including changes to periods, bleeding between periods, or bleeding after menopause)
Spotting
Abnormal vaginal discharge
Pelvic pain
A mass that can be felt in the lower abdomen
Unintentional weight loss
Urine or bowel issues (such as more frequent urges to urinate or constipation)
These symptoms may have other causes, and should be evaluated by a medical professional.
Different forms of uterine cancer are characterized by distinct features and biological behaviors:
Endometrial[2]: This is by far the most common form of uterine cancer in adults, accounting for 95% or more of all uterine cancers. It begins in the lining of the uterus (the endometrium). There are many subtypes of endometrial cancer, assigned based on the appearance of the cancer cells. Endometrial cancers are also assigned different types. Type 1 endometrial cancer is thought to be caused by excess estrogen, and tends not to spread quickly. Type 2 endometrial cancer grows faster and spreads outside the uterus more quickly; the outlook is poorer and treatment is generally more aggressive for this form.
Uterine sarcoma[3]: This rare form of uterine cancer forms in the myometrium–the thick muscle layer of the uterus–or in the connective tissues of the uterus. Uterine sarcomas include: some text
Uterine leiomyosarcoma: These tumors start in the myometrium and often spread quickly. They are the most common form of uterine sarcoma
Endometrial stromal sarcoma (ESS): These form in the stroma, or connective tissue, of the endometrium. Low-grade ESS tumors tend to grow slowly and may be responsive to hormone drugs. High-grade tumors tend to grow quickly and are difficult to treat.
There are also benign tumors that can form in the uterus. Depending on location and size, these may or may not require treatment.
Uterine cancer survival rates are based on how far the cancer has spread:
Localized: There is no sign the cancer has spread outside the uterus.
Regional: The cancer has spread to nearby structures or lymph nodes
Distant: The cancer has spread to distant parts of the body, such as the liver or bones.
Outcomes vary widely based on the type of uterine cancer. The 5-year survival rate for endometrial cancer at each stage is shown below:
The 5-year survival rate for various uterine sarcoma types at each stage are shown below:
Incidence
Below is the overall incidence of endometrial cancer by age group:
Risk Factors
There are several confirmed risk factors that contribute to an individual’s risk for uterine cancer:
Obesity: Numerous studies have linked higher BMI to increased risk of various types of cancer, and obesity is considered a strong risk factor for uterine cancers. Excess body fat can lead to higher levels of estrogen and insulin, as well as increased production of insulin-like growth factors; many uterine cancers are thought to have their origins in excess estrogen. Compared to healthy-weight women, uterine cancers are twice as common in overweight women, and three times as common in obese women. Higher BMI is also associated with chronic low-level inflammation, which can cause DNA damage over time and contribute to the development of cancers of many types.
Estrogen therapy: Estrogen therapy is often used to combat the symptoms of menopause, but it can significantly increase one’s risk of developing uterine cancers. When taken in conjunction with progestins, estrogen therapy has not been shown to increase the risk of these cancers.
Early menstruation/late menopause: Having more periods over the course of one’s lifetime increases the risk of uterine cancer. Individuals whose periods start before the age of 12, or who undergo menopause later than normal, are at higher risk (though early onset of menstruation increases risk less than late menopause).
Tamoxifen: This drug used to treat breast cancer acts like estrogen in the uterus, increasing one’s risk of developing uterine cancers. It is important to weigh the relatively small risk increase of this drug with the potential benefits in treatment.
Health conditions: some text
Polycystic ovary syndrome (PCOS): This condition changes the hormone balance in a woman’s body, increasing her levels of estrogen relative to progesterone. It can also cause infertility.
Type 2 diabetes: Individuals with type 2 diabetes have about twice the rate of uterine cancers as individuals without the disease.
Endometrial hyperplasia: This condition causes the endometrium to grow abnormally. If left untreated, mild hyperplasia turns into cancer in about 8% of cases, and complex atypical hyperplasia turns into cancer in about 29% of cases.
Endometriosis: Though more study is needed, it seems likely that endometriosis–a condition where endometrial tissue grows outside the uterus–increases the risk for uterine cancer.
Breast or ovarian cancer: The hormonal changes linked to these cancers can increase a woman’s risk of developing uterine cancer as well.
Genetic conditions: Some uterine cancers are likely caused by inherited genetic conditions, including Lynch syndrome, congenital retinoblastoma, and HLRCC (a rare family cancer syndrome). Additionally, some families have much higher rates of uterine cancer overall in the absence of known genetic risk factors, which may point to an as-yet-undiscovered genetic condition.
Prior pelvic radiation therapy: Used to treat some types of cancers, this targeted radiation increases the risk of uterine cancer.
Use of chemical hair straighteners: Long-term use of chemical hair straighteners has been shown to more than double one’s risk of developing uterine cancer.
Protective Factors
Several factors have been shown to have protective effects against uterine cancer:
Pregnancy: Pregnancy reduces a woman’s number of lifetime menstrual cycles and shifts the hormonal balance in the body towards progesterone over estrogen, both protective factors against uterine cancer.
Breastfeeding: Women who breastfeed their children have a lower risk of uterine cancer. The reduction in risk corresponds with overall duration of breastfeeding.
Oral contraceptives / IUD: These forms of contraception have both been shown to reduce one’s uterine cancer risk. The protective factor of oral contraceptives increases with longer use, and appears to remain for around 10 years after cessation.
Physical activity: Regular exercise can reduce your risk of several types of cancer through a combination of physiological, hormonal, and immunological changes, and has been shown to reduce the risk of uterine cancers. It can reduce inflammation, improve immune function, improve hormonal regulation, and lower insulin levels. The American Cancer Society recommends engaging in at least 150 minutes of moderate activity or 75 minutes of vigorous activity each week. Furthermore, data indicates that individuals can see significant incremental benefit with additional exercise.
Vegetable consumption: Vegetables are rich in various nutrients which have been shown to have protective effects against multiple cancers, including uterine. These foods contain a variety of antioxidants, which help neutralize free radicals in the body and reduce inflammation. The protective effect seems to be most closely tied to dark green and dark yellow vegetables, fresh legumes, and allium vegetables (such as onions and garlic).[7]
Coffee: Large studies have shown that coffee consumption has a protective effect against uterine cancer. Drinking four or more cups daily was associated with a 25% reduction in risk. [8]
Screening
Early detection of uterine cancer has a dramatic impact on prognosis. The 5-year survival rate for localized endometrial cancer (by far the most common form of uterine cancer) is around 95%, but drops to just 19% once the cancer has spread to distant parts of the body.
Depending on your age and risk factors, the optimal uterine cancer screening will vary:
Regular physical / pelvic exams: Physicals, and particularly regular pelvic exams, are the best first test for potential uterine cancer. If your doctor finds anything concerning, they will likely recommend more specific testing to determine the cause.
Ultrasound: Abdominal ultrasounds and/or transvaginal ultrasounds can show any abnormalities in the uterus, as well as the thickness of the endometrium (a thickened endometrium may be a sign of endometrial cancer).
Blood tests: A complete blood count (CBC) can measure different cells in the blood. Certain results, such as anemia, may indicate uterine cancer (though this result may have several more common causes).
CA-125 test: This blood test specifically looks for CA-125, a substance released by many endometrial and ovarian cancers (though not all; a negative result is not a guarantee these cancers are not present). Levels can also indicate whether a diagnosed cancer has progressed.
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