Endometrial cancer may remain hidden for several years at the longest, but the exact hiding time varies from person to person. In the early stage of endometrial cancer, the lesion can be detected only under microscope, but there is no lesion visible to the naked eye, and the exact length of this period is related to many factors, and it may not be detected for years. If the endometrial cancer is asymptomatic and the patient does not undergo routine physical examination, it is possible that it may remain undetected as well. If the patient undergoes regular physical examination and finds other manifestations such as endometrial thickening or unevenness, and then further diagnostic scraping is done, it may be detected earlier. Therefore, the duration of concealment of endometrial cancer is related to whether the patient has standardized medical examination and whether he/she has paid attention to the characteristics and manifestations of the disease. If irregular vaginal bleeding or unexplained vaginal discharge, bloody leucorrhea, or chronic abdominal pain is found in early stage, one must go to gynecology department of hospital for relevant examination in time and then clarify whether there is any lesion.