A one to two-year course of tamoxifen approximately doubles the risk of endometrial cancer, and a five-year course of therapy quadruples that risk. Raloxifene, a similar drug, did not raise the risk of endometrial cancer. Previously having ovarian cancer is a risk factor for endometrial cancer, as is having had previous radiotherapy to the pelvis. Specifically, ovarian granulosa cell tumors and thecomas are tumors associated with endometrial cancer. Low immune function has also been implicated in endometrial cancer. High blood pressure is also a risk factor, but this may be because of its association with obesity. Sitting regularly for prolonged periods is associated with higher mortality from endometrial cancer. The risk is not negated by regular exercise, though it is lowered. Protective factors
Smoking and the use of progestin are both protective against endometrial cancer. Smoking provides protection by altering the metabolism of estrogen and promoting weight loss and early menopause. This protective effect lasts long after smoking is stopped. Progestin is present in the combined oral contraceptive pill and the hormonal intrauterine device (IUD). Combined oral contraceptives reduce risk more the longer they are taken: by 56% after four years, 67% after eight years, and 72% after twelve years. This risk reduction continues for at least fifteen years after contraceptive use has been stopped. Obese women may need higher doses of progestin to be protected. Having had more than five infants (grand multiparity) is also a protective factor, and having at least one child reduces the risk by 35%.
Kerato-limbal allograft (KLAL) involves transplantation from someone who has died and donated their organs. KLAL can be used for cases of bilateral LSCD when a living related donor is not available, or for patients with unilateral LSCD, who dont want to jeopardise their healthy eye. However, most of these types of transplant fail within five years. KLAL has a number of limitations: the graft is usually up to 24 hours old before retrieval and a further period of time is often required to screen the cadavers blood before the tissue can be used; often the limbus is found to be damaged as the tissue is not immunocompatible, there is a high risk of rejection between the recipient and the donor cadaver and studies report only a temporary success in term of transplant effectiveness, with most failing after 5 years. A recent procedure, less invasive than CLAU, which so far has been tested only in unilateral cases, is simple limbal epithelial transplantation (SLET). In this procedure, healthy limbal tissue from the patients good eye is cut into a number of pieces and transferred directly to human amniotic membrane covering the cornea in the damaged eye. Studies published so far have only investigated the procedure in unilaterally affected patients, and the long-term effectiveness of the technique is yet to be proven. Another recent innovation is cultivated limbal epithelial transplant (CLET), either autologous (where donor and recipient are the same patient) or allogenic (where donor and recipient are different patients).