The kidneys, two large bean-shaped organs in the abdomen, separate waste products from the blood and produce urine. When cancer arises in the kidneys it is usually in the renal cells, the cells that line the tiny tubes where blood is filtered. About 51,200 adults are diagnosed with kidney cancer each year in the United States, and renal cell cancer accounts for 85 percent of cases. The disease is almost twice as prevalent in men as women, probably because more men than women smoke have smoked, and men have been more likely to be exposed to carcinogens in the workplace. African-Americans have a slightly higher risk of developing kidney cancer over people of other races. However, the reasons for this are not understood.
There are a number of risk factors for kidney cancer: smoking; being overweight, which is believed to change certain hormones and increase the chance cancer develops; being exposed to certain workplace chemicals such as cadmium, asbestos, some herbicides, benzene, and organic solvents, especially trichloroethylene. People with a family history of kidney cancer and certain inherited genetic conditions (hereditary renal oncocytoma, hereditary papillary renal cell carcinoma, hereditary leiomyoma-renal cell carcinoma, von Hippel-Lindau disease, Birt-Hogg-Dube (BHD) syndrome) are also at increased risk of developing kidney cancer, as are those with advanced kidney disease, high blood pressure (although this may be from medication used to treat high blood pressure), and those who have used certain medications (Phenacetin, diuretics).
Kidney cancer may cause the following symptoms: blood in the urine, persistent pain in the side, a lump or mass in the side or the abdomen, unexplained weight loss, fever, and fatigue. Conditions other than kidney cancer can cause these symptoms, and patients with any symptoms should see a doctor to determine the cause.
A variety of tests may be used to diagnose kidney cancer. They include: a urine test, a blood test to assess kidney function, a CT scan and/or MRI, and ultrasound exam. To confirm a diagnosis of kidney cancer, doctors sometimes take a biopsy (a small tissue sample) of the kidney that is then examined by a pathologist. Other times, the presumptive diagnosis is made based upon a combination of factors taken from medical history, physical examination, and scan and the kidney (or part of the kidney) is removed.
Doctors determine the best treatment approach for each patient with kidney cancer by taking into account the type, location, and stage of the disease as well as the patient's age and physical health. Surgery to remove the tumor is usually the first choice of treatment, but not all patients are good candidates for kidney surgery. In these cases doctors may treat patients with radiation, chemotherapy, immunotherapy, targeted therapies, or a combination of these.
With surgery, minimally invasive approaches such as laparoscopy are generally preferable to open procedures because they can more easily allow surgeons to remove the tumor but still leave enough tissue for the kidney to function.
Some patients with small, localized tumors are candidates for "percutaneous cryoablation," in which specialists freeze the tumor. During this treatment surgeons insert several needles into the kidney tumor. Argon and helium gas circulate through the needles, lowering the temperature to -40°C for several minutes. Over time, the tumor tissue "scars down" and eventually disappears.
Some patients' kidney cancer is more advanced, and surgery is not a possibility. Our uro–oncologists sometimes treat advanced kidney disease with immunotherapies, substances designed to boost or restore the natural defenses against the cancer. Patients may also be treated with new targeted therapies – drugs that take aim at blocking specific pathways active in the progression of kidney cancer. There have been a large number of these types of drug approved in the last several years. In patients whose kidney cancer has spread to other organs, doctors may use external beam radiation with chemotherapy as the primary treatment.