Kidney cancers are among the 10 most common cancers in men and women in the United States. According to the American Cancer Society, about 62,700 new cases of kidney cancer will be diagnosed in the United States in 2016, and 14,240 people will die from the disease. Kidney cancers are rarely diagnosed in people younger than 45 years.
The kidneys are responsible for filtering the blood to remove extra water, salt, and waste products, which eventually become urine. The kidneys are also respon
sible for controlling blood pressure and making sure that the body has enough red blood cells.
Kidney cancers develop when cells in the kidneys begin to grow out of control; the cells can spread to the lungs, bones, or liver. After spreading, kidney cancer cells may form new tumors in different parts of the body.
Types of Kidney Cancers
Renal-cell carcinoma (cancer in the lining of the tubules of the kidney) is the most common type of kidney cancers; about 90% of kidney cancers are renal-cell carcinomas.
Renal-cell carcinoma is divided into several subtypes, including clear-cell renal-cell carcinoma; papillary renal-cell carcinoma; and chromophobe renal-cell carcinoma.
Other types of kidney cancers include transitional-cell carcinoma (urothelial); Wilms tumors, and renal sarcomas.
Certain lifestyles and medical conditions may increase the risk for kidney cancer. The main risk factors for kidney cancers are:
- Age older than 45 years
- Workplace exposures to certain environmental substances, such as asbestos, cadmium, herbicides, and organic solvents
- High blood pressure
- Gender: men are at greater risk than women
- Race: African Americans and American Indians/Alaska Natives are at a slightly greater risk than Caucasians
- Family history: people with a strong family history of kidney cancer, especially siblings, are at increased risk
A few genetic syndromes run in families, such as changes (mutations) in the VHL, MET, FH, FLCN, SDHB, and SDHD genes; these increase the risk for kidney cancer. Changes in the SDHB and SDHD genes can cause Cowden-like syndrome, which puts people at greater risk for breast, thyroid, and kidney cancers.
Therefore, it is important to let your physician know if anyone else in your family has been diagnosed with cancer.
Usually, early kidney cancers do not have any symptoms; as the tumors grow larger, symptoms often appear. The most common symptoms include blood in the urine, continuous pain in the side, a lump or mass on the side or lower back, weight loss, anemia, swelling of the ankles or legs, and fatigue. These symptoms, however, may be caused by many other conditions.
Many kidney cancers are found early, before they have spread to other parts of the body; some cancers are found at later stages. Kidney cancers are often found by accident, during tests for some other illness, such as gallbladder disease.
The diagnosis includes medical history and physical exam; laboratory tests, including blood work and urine test; and imaging tests, such as ultrasound, intravenous pyelogram, CT scan, MRI, and renal arteriogram.
Biopsy (removal of tissue to look for cancer cells) is not usually performed to diagnose kidney cancer, but it may be done if imaging results are not clear.
Treatment options for kidney cancers include surgery, radiation therapy, ablation and other local therapies, targeted therapy, immunotherapy, chemotherapy, and watchful
waiting, or a combination of these. When choosing a treatment option, it is important to consider the stage of the cancer; overall health; treatment side effects; and the likelihood of curing the cancer, extending life, or relieving symptoms.
Surgery is the main treatment for most kidney cancers.
Radiation therapy is not often used to treat kidney cancers but rather the symptoms, such as pain or bleeding.
Chemotherapy is not a standard treatment for kidney cancer. Instead, chemotherapy is often used in patients with kidney cancer only after the use of targeted drugs or recently with immunotherapy. However, some patients have benefited from chemotherapy drugs as well.
Immunotherapy. Immunotherapy uses the body’s immune system to kill cancer cells. Cytokines are a type of immunotherapy and include interleukin-2 and interferon-alpha; these therapies have been shown to shrink kidney cancers in some patients.
Other immunotherapies include immune checkpoint inhibitors. The body contains immune checkpoints to prevent normal cells from being attacked by the immune system; sometimes, cancer cells use these checkpoints to avoid being destroyed. Immune checkpoint inhibitors include drugs that increase the body’s immune response against cancer cells.
Opdivo (nivolumab) is the first immune checkpoint inhibitor approved by the FDA for patients with advanced (metastatic) renal-cell carcinoma. Opdivo is given intravenously every 2 weeks. In clinical trials, Opdivo extended survival of patients with advanced renal-cell carcinoma.
Targeted therapies. Targeted therapies are designed to treat specific genes, proteins, or tissue environments of kidney cells to block the cancer from growing and spreading. Targeted drugs are proving to be especially important in kidney cancers, because chemotherapy has not been shown to be very effective. These targeted drugs are commonly used as first-line treatment for advanced kidney cancers.
Currently available targeted therapies approved by the FDA for patients with advanced renal-cell carcinoma include Avastin (bevacizumab), which is used in combination with interferon-alpha and is given intravenously; and Torisel (temsirolimus), which is given as an intravenous infusion. The other targeted drugs are taken orally as a pill and include Nexavar (sorafenib); Afinitor (everolimus), which is used after treatment failed with Nexavar or Sutent; Votrient (pazopanib); and Sutent (sunitinib).