The symptoms of breast cancer during lactation are mainly obvious lumps inside the patient’s breast, but sometimes the patient may mistake them for hard lumps formed by milk stagnation and does not pay enough attention to them. In addition, the size of the lump may gradually increase as time goes on. If the lump is large, it may lead to localized skin depression and sometimes the patient’s milk may be bloody or light blood. Some patients experience pain or discomfort, and some patients do not experience discomfort. Therefore, when a patient has a hard node or lump inside the breast, it is important to go to the hospital in time for examination, because sometimes it is a benign lesion, and sometimes it is a malignant tumor.