The kidney is an important organ in the body for excreting metabolic waste and maintaining a stable internal body environment. Many internal diseases (such as diabetes and hypertension) can lead to impairment or even failure of kidney function, with the end result being lifelong kidney replacement therapy (dialysis or kidney transplantation). Similarly in the treatment of kidney tumors, we remove the whole kidney or part of it, which can also have an impact on kidney function. Some studies have confirmed that the good or bad kidney function after kidney tumor surgery is closely related to the volume of kidney tissues removed, and the more kidney volume lost the more kidney function decreases. Therefore, in order to avoid the loss of kidney function as much as possible, we will keep as much kidney tissue as possible. For example: for small tumors located on the surface of the kidney (Figure 1, image source Cleveland Clinic), we will try to take kidney-conserving surgery to remove the tumor and preserve the kidney. This way the normal kidney tissue preserved in the kidney with the long tumor is still able to play the role of excreting waste. For some tumors that are large and located near the blood vessels of the kidney (as in Figure 2, image credit Cleveland Clinic), kidney-preserving surgery can be attempted, but the risk of kidney-preserving failure or complications such as bleeding and urinary leakage increases accordingly. So I think the principle of kidney tumor treatment nowadays is to try to preserve as much kidney tissue as possible while making sure the tumor is cut cleanly and the surgery is safe. Now, I am studying in the Urology Department of Cleveland Clinic, which has been ranked the top in the United States and is ranked the first in the country this year. The hospital has a philosophy that “every kidney should be considered for preservation”, in other words, when a doctor sees a kidney cancer patient, the first thing that comes to their mind is “can this kidney be preserved? . The unit where I work also adheres to this principle, and in the past few years, about 50% of the patients undergoing kidney cancer surgery have been kidney-preserving patients.