Hi, I can understand your concerns. The decision to remove partial vs whole of kidney depends on many factors like - size of mass, location of mass, function of both kidneys, fitness of patient and associated conditions like diabetes/hypertension which can affect the kidney function in the long run. Many of these factors are known before surgery from history, blood investigations and Computed Tomography (CT scan). The standard treatment for a mass less than 4 cm in size is partial removal. Partial removal can be safely performed up to 7 cm size (larger tumors can be removed based on location and function of opposite kidney). The idea behind partial removal is to preserve as much kidney function as possible since the remaining kidney in the same side will still continue to function. This is beneficial in the long run. However partial removal needs more expertise and is associated with a slightly more risk of complications. There are scoring systems like RENAL nephrometry (www.nephrometry.com), which can predict the complexity of mass and thus guide the Urologist in making the decision. Though all these can give an idea about the choice of procedure, the decision for borderline masses may need to be taken in operation room only. The minimally invasive surgery can be either robotic or laparoscopic. While robotic surgery is a costly procedure, it is relatively easy to perform when compared to laparoscopic surgery. I can guide you further if you can provide the CT scan report, other investigations (Hemoglobin, serum creatinine, Liver function) and details of any medical condition of your husband. Wish your husband a safe surgery, Dr. Raguram.