According to the American Cancer Society, endometrial cancer is the most common cancer of the female reproductive organs in the United States, and the average age of women diagnosed with endometrial cancer is 60. It is uncommon in women under the age of 45, and it affects mainly post-menopausal women. Endometrial cancer is more common in Black women than White women, and Black women are more likely to die from it. The estimates for cancer of the uterus in the United States for 2023 are 66,570 new cases of uterine cancer and 12,940 deaths from uterine cancer. These estimates include both endometrial cancers and uterine sarcomas. Up to 10% of uterine body cancers are sarcomas, so the actual numbers for endometrial cancer cases and deaths are slightly lower than these estimates.

The most common and most accurate way to diagnose endometrial cancer is with an endometrial biopsy. According to a study published in the American Family Physician, patients with endometrial specimens that show atypia have about a 25 percent likelihood of progressing to carcinoma, compared with less than 2 percent of those without atypia. The presence of atypia indicates risk for progression to cancer. In several studies of women with endometrial hyperplasia, more than 80 percent of those without atypia responded to progestin therapy, compared with only 50 percent of those with atypia. Carcinoma developed in 25 percent of patients with atypia as opposed to less than 2 percent of those without atypia.

A study published in PubMed found cancer in 2 of 61 patients with simple hyperplasia without atypia (3.2%), none of the 6 patients with atypical hyperplasia was found simple cancer (0%) . Another retrospective study found that the prevalence of endometrial cancer in patients with atypical endometrial hyperplasia ranged between 5.9% and 53.1% in 15 different studies.

In summary, the percentage of endometrial biopsies that are cancerous varies depending on the presence of atypia and other factors. Patients with endometrial specimens that show atypia have about a 25 percent likelihood of progressing to carcinoma, compared with less than 2 percent of those without atypia.