Preliminary research has been promising, and a stage II trial for ridaforolimus was completed by 2013. There has also been research on combined ridaforolimus/progestin treatments for recurrent endometrial cancer. Bevacizumab and tyrosine kinase inhibitors, which inhibit angiogenesis, are being researched as potential treatments for endometrial cancers with high levels of vascular endothelial growth factor. Ixabepilone is being researched as a possible chemotherapy for advanced or recurrent endometrial cancer. Treatments for rare high-grade undifferentiated endometrial sarcoma are being researched, as there is no established standard of care yet for this disease. Chemotherapies being researched include doxorubicin and ifosfamide.There is also research in progress on more genes and biomarkers that may be linked to endometrial cancer. The protective effect of combined oral contraceptives and the IUD is being investigated. Preliminary research has shown that the levonorgestrel IUD placed for a year, combined with six monthly injections of gonadotropin-releasing hormone, can stop or reverse the progress of endometrial cancer in young women; specifically complex atypical hyperplasia however the results have been inconclusive. An experimental drug that combines a hormone with doxorubicin is also under investigation for greater efficacy in cancers with hormone receptors. Hormone therapy that is effective in treating breast cancer, including use of aromatase inhibitors, is also being investigated for use in endometrial cancer. One such drug is anastrozole, which is currently being researched in hormone-positive recurrences after chemotherapy. Research into hormonal treatments for endometrial stromal sarcomas is ongoing as well.
In the United States, they are more common in white women, particularly those with a history of endometrial hyperplasia. Type I endometrial cancers are often low-grade, minimally invasive into the underlying uterine wall (myometrium), estrogen-dependent, and have a good outcome with treatment. Type I carcinomas represent 75–90% of endometrial cancer.Type II endometrial carcinomas usually occur in older, post-menopausal people, in the United States are more common in black women, and are not associated with increased exposure to estrogen or a history of endometrial hyperplasia. Type II endometrial cancers are often high-grade, with deep invasion into the underlying uterine wall (myometrium), are of the serous or clear cell type, and carry a poorer prognosis. They can appear to be epithelial ovarian cancer on evaluation of symptoms. They tend to present later than Type I tumors and are more aggressive, with a greater risk of relapse and/or metastasis. Endometrioid adenocarcinoma
In endometrioid adenocarcinoma, the cancer cells grow in patterns reminiscent of normal endometrium, with many new glands formed from columnar epithelium with some abnormal nuclei. Low-grade endometrioid adenocarcinomas have well differentiated cells, have not invaded the myometrium, and are seen alongside endometrial hyperplasia. The tumors glands form very close together, without the stromal tissue that normally separates them. Higher-grade endometrioid adenocarcinomas have less well-differentiated cells, have more solid sheets of tumor cells no longer organized into glands, and are associated with an atrophied endometrium. There are several subtypes of endometrioid adenocarcinoma with similar prognoses, including villoglandular, secretory, and ciliated cell variants.