The disease, which targets the tissue lining the uterus, struck 42,160 women in 2009, according to the latest statistics from the National Cancer Institute (NCI). It mostly affects women over the age of 50 and more white women than African Americans.
Endometrial cancer is the most common gynecological malignancy and the fourth most common among all cancers affecting American women, according to Dr. Andrea Mariani, associate professor of gynecology and surgery at the Mayo Clinic, who has studied the disease for 15 years.
But the good news is that about 70 to 80 percent of all endometrial cancers - both Type 1 and Type 2 - are curable, according to Mariani.
Type 1 is hormone-dependent with a high cure rate. Type 2, which occurs in only 15 percent of endometrial cancer, is more aggressive and usually fatal.
Only breast, lung and colon cancer affect more American women.
"This cancer is very common, but most of the time it's a good cancer because we find it very early," he said. "It happens most often in menopausal women and there is usually bleeding. In places like the U.S., where people are in general educated, women go to their doctors early, they see something unusual and it scares them a bit and it's diagnosed early."
Risk factors for the endometrial cancer include age, obesity and hormone replacement therapy (HRT) for the symptoms of menopause and prevention of osteoporosis.
Women who take HRT with estrogen but no progesterone face a higher cancer risk. Higher dosage means higher risk, according to NCI.
Doctors advise women to consult with their own physicians about the risk versus benefits of hormone replacement therapy.
"If [HRT] is counterbalanced with progesterone, it's less of a problem," Mariani said. "Those women are usually well-screened and followed by a doctor. But it is something they need to know."
Other risk factors include obesity and its related conditions, such as diabetes and high blood pressure. Fat cells convert androgen to estrogen, which increases risk in hormone-dependent cancers like Type 1 endometrial cancer.
Women taking Tamoxifen to treat or to prevent breast cancer are also at higher risk, due to the estrogen-related effect of the drug on the uterus. Women using this drug should be more carefully monitored.
About 5 to 10 percent of endometrial cancers are due to a family history, especially in families with a history of colon cancer, according to Mariani.
Symptoms of endometrial cancer usually occur after menopause, but can start at its onset. Women may notice abnormal vaginal bleeding, which may start as a watery, blood-streaked flow that gradually contains more blood.