Breast tumor with kidney metastasis may cause hydronephrosis. If the breast tumor has metastasis to the kidney, the enlarged tumor cells compress the kidney tissue and may cause hydronephrosis, which often indicates that the cancer is in the advanced stage. It is recommended to actively cooperate with the doctor to alleviate the symptoms and improve the prognosis of the disease through radiotherapy and targeted drug treatment. The chemotherapy drugs that patients can choose include cyclophosphamide, cytarabine, paclitaxel, etc.; targeted drugs include trastuzumab, olaparib, etc.. Drugs are recommended to be used in strict compliance with medical advice, the emergence of adverse reactions to timely consultation, drug allergy is prohibited. After timely treatment, it can significantly reduce the tumor lesions, relieve discomfort, improve the quality of life of patients, prolong the survival time of patients, and improve the prognosis of the disease. It is recommended that breast cancer patients should consult regular hospitals in time and standardize the treatment under the guidance of doctors in order to improve the survival rate.