During the menstrual cycle, due to the influence of various related endocrine hormones, some physiological changes of enlargement and rejuvenation of the breast will occur, causing the breast tissue to be in various degrees of congestion and edema, and these changes may interfere with the doctor’s examination of the location, size and nature of the breast lump, thus affecting the judgment of the nature of the breast lump. So, what is the most appropriate time for examination? The best time to examine the breast is usually around the 9th to 10th day of menstruation, when estrogen has the least effect on the breast, the breast is in a relatively static state, and lesions or abnormalities in the breast can be easily detected. Older women who are post-menopausal can choose the time to visit the doctor at will because their estrogen is reduced and they are less affected by endocrine hormones. However, you should be reminded that the most common age of breast cancer is between 45 and 55 years old. If breast lesions are detected during breast self-examination or screening, you should seek early medical consultation and follow the doctor’s instructions. Some patients who are in clinical remission of benign breast disease do not have regular follow-up examinations for a long time, and when the original benign lesions become malignant, it will be very difficult to cure them. Therefore, early consultation should be an important principle, and choosing the best time for consultation is an important means to improve the correct diagnosis.