The most common type of kidney tumor in America is a renal cell carcinoma, and the number of cases has been increasing. As of 2007, there were approximately 51,000 cases and 8,000 deaths every year from renal cancer, according to David Swanson, M.D., writing in the "The Merck Manual for Healthcare Professionals." People with this tumor develop the disease when they are between 50 and 70 years old.
Risk Factors
Cigarette smoking is a risk factor for renal cell carcinoma. Most studies, in fact, show that smoking doubles the risk. As in other cancers associated with smoking, the risk decreases when people stop smoking. But in renal cell carcinoma, it takes a much longer time for the risk to decrease. The risk factors also include exposure to cadmium, solvents, asbestos and certain dyes, as well as obesity and a diet high in fats, protein, red meat or fried foods. Badrinath Konety, M.D., in "Smith's General Urology," writes that there are hereditary forms of renal cell carcinoma. One form involves changes on chromosomes three and eight. In a form called hereditary papillary renal carcinoma, several tumors grow on both kidneys. In Von Hippel-Lindau disease, which is hereditary, people have tumors in the retina of the eye and cerebellum of the brain, as well as tumors in the kidney.
Symptoms
The symptoms for this type of cancer include hematuria, or blood in the urine. The hematuria can be gross or microscopic. Gross hematuria means people see red urine when they urinate. In microscopic hematuria, the urine is not red, but a lab test will detect red blood cells in the urine sample. The symptoms may also include pain in the lower back area and a mass in the abdominal area. But most people do not have the symptoms of hematuria until the cancer is in an advanced stage, explains Patricia Cornett, M.D., in "Current Medical Diagnosis & Treatment." If people are coughing, this can be a sign that the renal cell carcinoma has spread to the lungs. If they have pain in their bones, this may be a sign that the cancer has spread to the bone.
Paraneoplastic Syndrome
Paraneoplastic syndrome is the term used to describe additional symptoms or disease that are caused because the cancer secretes hormones and does not abide by any controls. The kidney normally secretes erythropoietin, or EPO. This is a hormone that stimulates the bone marrow to produce red blood cells. But in renal cell carcinoma, the tumor secretes high levels of EPO. This leads to high levels of red blood cells, or what is called polycythemia. Renal cell carcinoma also leads to hypercalcemia, or high levels of calcium in the bloodstream. This is because the tumor secretes a hormone called PTHrp. This hormone has the job of increasing calcium levels in the blood.
References
- "Current Medical Diagnosis & Treatment 2010"; Stephen McPhee, M.D., Maxine Papadakis, M.D.; 2010
- "Smith's General Urology"; Emil Tanagho, M.D., Jack McAninch, M.D.; 2008
- The Merck Manual for Healthcare Professionals: Renal Cell Carcinoma
