Kidney Disease and Kidney Cancer Survivors

25 million Americans suffer from kidney disease. After a nephrectomy, the second kidney usually grows and takes over the filtration function of the missing kidney. However, this is not always the case, and many kidney cancer survivors also suffer from early stage kidney disease. We hear a lot about creatinine level as being a marker for kidney disease, but it is only one factor. The normal creatinine level varies depending on one's individual characteristics, so the standard measure of kidney function is GFR, or Glomerular Filtration Rate, which is a combination of creatinine level, age, gender, and ethnicity. GFR is measured in milliliters per minute of blood clearance by the kidneys with 100 mL/min considered normal. For example, a GFR of 50 would indicate a 50% filtration or kidney function rate.

Kidney disease is broken down into five stages, with Stage 1 defined as a GFR greater than 90 mL/min (close to a normal) to Stage 5, with a GFR of less than 15 mL/min, indicating kidney failure and requiring dialysis. The GFR normally decreases with age and it is higher in men and African-Americans based on the same creatinine level because men and African-Americans have higher muscle mass, which normally produces a higher creatinine molecule than say women would. Of the 20 million Americans who have kidney disease, based on the GFR definition, only 300,000 have Stage 5. For many people kidney disease is asymptomatic so a blood test revealing a high creatinine level is often the first indicator of a problem. When the GFR falls into the Stage 3 level, i.e. 15-59, it is time to see a nephrologist. To see whether your GFR falls below 60, go to the following URL to calculate GFR or filtration rate, http://nkdep.nih.gov/professionals/gfr_calculators/orig_con.htm.

After a nephrectomy, the remaining kidney usually takes over the body's filtration burden leading to normal or near-normal kidney function. However, in some cases, the remaining kidney is not able to handle the added responsibility and the creatinine level shoots up and the GFR level falls. Risk factors for lower kidney function after nephrectomy are hypertension, diabetes, and proteinuria (high levels of protein in the blood). Anyone diagnosed with kidney cancer who has these risk factors, should consider having nephron-sparing surgery, i.e. a partial nephrectomy, if possible, in order to preserve kidney function.