Breast cancer in men does not develop instantly. Breast cancer is a malignant tumor disease caused by malignant lesions in the breast. Although women are the main incidence group of breast cancer, men may also be affected by breast cancer. Although the exact cause of breast cancer is still unclear, it is undeniable that the occurrence of this malignant tumor disease is caused by a combination of factors such as heredity, environment and gene mutation. Breast cancer in men does not come on suddenly, because the formation and onset of breast cancer itself is a relatively long process. Whether it is breast cancer or other malignant tumors, all of them belong to chronic consumptive diseases and will not develop suddenly. If men find any discomfort in their breasts, they should go to regular hospitals in time, and be examined by professional doctors, and then be treated accordingly after a clear diagnosis is made.