Another factor that’s taken into account when considering surgery is a patient’s weight. Usually, doctors look at a calculation called the Body Mass Index, or BMI, that takes both height and weight into account. If a person’s BMI is lower than this, they’re underweight; if it’s higher, they’re overweight. If the BMI is over 30, they’re considered obese. Although obesity is a risk factor for some surgeries, it doesn’t appear to be for robot-assisted cystectomy. Roswell Park patients having this procedure have ranged from underweight to obese.