Low urine in advanced stage of breast cancer may be related to urethra compression, low food intake, kidney failure and other reasons. 1. Urethral compression: when the tumor has metastasized in the advanced stage of breast cancer, it may compress the urethra, resulting in difficulty in urination and low urine output. 2. Low food intake: patients with advanced breast cancer usually lose their appetite, the amount of food and water intake will be obviously reduced, and the body consumption of advanced patients is large, which leads to low urine intake in advanced breast cancer. 3. Renal failure: if cancer cells of advanced breast cancer patients metastasize to distant places, leading to renal failure and serious damage of renal function, it will cause low urine output. It is suggested that patients with advanced breast cancer can consult doctor or go to doctor for examination in time when symptoms of oliguria appear, so as to clarify the cause and treat it in time.