1. Insufficient scientific knowledge of breast cancer, lack of awareness of the clinical characteristics of breast cancer and lack of vigilance to this disease in daily life. 2.Early breast cancer is a painless lump, and the body can be free of any discomfort, which neither affects life nor work. 3. A few women are bound by stereotypes, old-fashioned thinking, shy to check their bodies, unwilling to expose their breast, and even more unwilling to go to hospital for examination. 4.For the sake of convenience, they listen to the nonsense of a certain person or believe too much in the diagnosis of a certain doctor or instrument, relax their vigilance and do not go for further examination. 5.Some people have read some books on tumor or are influenced by people around them and suffer from cancer fear, so they are very afraid that they have breast cancer and dare not go to hospital for examination. 6.The fast pace of life, too busy to care about their own body, even if they have discomfort, they just deal with it. This causes many breast cancer patients to delay the time of early diagnosis.