Endometrial cancer has the second highest incidence of female genital tumors at about 25.7/100,000, and most endometrial cancers are histologically endometrioid adenocarcinomas with precancerous lesions. If left untreated, endometrial hyperplasia may develop into endometrial cancer. Endometrial hyperplasia is divided into four types based on histological manifestations: simple hyperplasia, complex hyperplasia, simple atypical hyperplasia, and complex atypical hyperplasia. Simple hyperplasia does not usually progress to endometrial cancer (1% risk), but complex atypical hyperplasia has an approximately 25% risk of endometrial cancer. There are several known risk factors for endometrial hyperplasia and endometrial cancer risk: excess estrogen (either increased synthesis in obese women or intake of non-antagonistic estrogen can lead to altered glandular proliferation), diabetes mellitus, nulliparity and polycystic ovary syndrome. If the patient’s main symptom is irregular vaginal bleeding, endometrial pathology should be suspected. Ultrasonography can help rule out other lesions (polyps, fibroids) and assess the thickness and status of the endometrium. Endometrial tissue samples can further assist in the diagnosis. Clinicians can obtain tissue samples by diagnostic curettage, Pipelle biopsy or hysteroscopy. However, all of these methods may miss the diagnosis and result in false negative results. Once endometrial hyperplasia is diagnosed, surgery or pharmacologic treatment is required. If medication is considered, which medication is more effective? Professor Hashim et al. of the Department of Obstetrics and Gynecology, Faculty of Medicine, Mansoura University, Egypt, summarized the studies on the efficacy of two pharmacological treatments, levonorgestrel intrauterine device (LNG-IUS) and oral progestin, for the treatment of endometrial hyperplasia without atypical hyperplasia and published the results in Am J Obestet Gynecol. The systematic review includes the results of seven randomized controlled trials. Only patients without atypical hyperplasia treated with LNG-IUS or oral progestin and followed for 3 to 24 months were included. The outcome analysis included 766 patients (329 patients were treated with LNG-IUS and 437 patients were treated with oral progestins). The oral progestins included medroxyprogesterone acetate, norethindrone acetate, and didrogestrel. Patients treated with LNG-IUS were found to have significantly better outcomes than those in the oral progestin group. The longer the follow-up period, the more pronounced the benefit of LNG-IUS; at 24 months, the OR was 7.46. The efficacy of LNG-IUS was significantly better than that of oral progestin in both simple and complex hyperplasia. However, there was no significant difference in the frequency of irregular vaginal bleeding between the two groups. Patients requiring hysterectomy were significantly less likely in the LNG-IUS group than in the oral progestin group. Treatment of simple or complicated endometrial hyperplasia with LNG-IUS was significantly better than oral progestin. The targeted treatment for endometrial cancer is hysterectomy. However, surgical treatment does not apply to all patients. Some patients still want to preserve their fertility, and others are not physically able to tolerate surgical treatment. In these cases, patients may be given long-term high-dose progestin therapy. Progestins have an anti-proliferative effect and may also reduce further glandular mutations. LNG-IUS has several advantages over oral preparations. One, compliance is better than with oral formulations. Second, side effect concerns are more favorable because LNG-IUS is administered locally rather than released systemically. The significant increase in local progestin concentration can achieve the effect of intrauterine treatment compared to oral preparations, and therefore the treatment is more effective. In conclusion, the use of LNG-IUS for the treatment of simple or complicated endometrial hyperplasia is clearly superior to oral progestins. However, randomized trials included only patients without atypical hyperplasia. Most studies had a follow-up of less than one year; further studies are needed for long-term follow-up effects. Since there are no data from studies demonstrating the efficacy of LNG-IUS in patients with atypical hyperplasia, caution should be exercised in such cases.