Cancer of the kidney, depending on its size and location, can impact the ability of the organ to carry out any of its normal functions.

Although blood in the urine can be one of the early warning signs of kidney cancer, there are often no indicators, and it is frequently found incidentally, or upon examination because of another health issue. Some risk factors for kidney cancer include genetic factors, smoking, obesity, and lifestyle factors.

What Kidneys Do

The kidneys are bean-shaped organs located just below the ribcage in the middle of the back. “In general terms, the kidney functions as a complex filter system, clearing certain unwanted byproducts from our bloodstream while also reabsorbing and regulating levels of other important factors,’” says Will Lowrance, MD, MPH, Assistant Professor, Urologic Oncology at Huntsman Cancer Institute at the University of Utah in Salt Lake City. “The final product containing the filtered and excreted materials from the bloodstream is urine.” Furthermore, he says kidney play a key role in the homeostasis of blood pressure and electrolytes and also has endocrine functions, producing hormones that impact blood pressure and red blood cell production.

When It’s Cancer

Cancer of the kidney, depending on its size and location, can impact the ability of the organ to carry out any of its normal functions. “For example, a large renal cell cancer can infiltrate and destroy/replace the normal kidney parenchyma, leading to loss of its ability to adequately filter blood,” says Dr. Lowrance. Certain kidney cancers, Dr. Lowrance adds, impact the kidneys ability to regulate blood pressure or even red blood cell production. “Some tumors involving the kidney can block the collecting system or ureter, leading to hydronephrosis—meaning the urine cannot adequately drain down into the bladder,” he says.

Risk Factors

There are some known risk factors for renal cell cancer, such as smoking, obesity, and renal disease. “It has long been known that end-stage renal disease and specifically patients on dialysis are at higher risk of kidney cancer,” Dr. Lowrance says. Additionally, he says, data are emerging that patients with chronic kidney disease may also be at higher risk of developing renal cancer, and some data suggest that hypertension may also be a risk factor. 

Some genetic factors predispose people to kidney cancer, including familial syndromes like Von Hippel-Lindau Disease, an inherited mutation of a gene that normally regulates the growth and division of cells. This mutation of the gene either prevents or causes abnormal production of the resulting protein, leading to the inability to effectively regulate the survival and division of cells, causing them to grow and divide uncontrollably. It is characterized by the formation of cysts or fluid-filled sacs in various areas of the body, such as the pancreas and kidneys.

New Advances

In January, 2012, the U.S. Food and Drug Administration (FDA) approved Inlyta (axitinib) to treat patients with advanced kidney cancer (renal cell carcinoma) that has not responded to another drug for this type of cancer.

Renal cell carcinoma is a type of kidney cancer that starts in the lining of very small tubes in the kidney. Inlyta works by blocking certain proteins called kinases that play a role in tumor growth and cancer progression. Inlyta is a pill that patients take twice a day.

“This is the seventh drug that has been approved for the treatment of metastatic or advanced kidney cell cancer since 2005,” says Richard Pazdur, MD, director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research. “Collectively, this unprecedented level of drug development within this time period has significantly altered the treatment paradigm of metastatic kidney cancer, and offers patients multiple treatment options.”

Other recently approved drugs for the treatment of kidney cancer include sorafenib (2005), sunitinib (2006), temsirolimus (2007), everolimus (2009), bevacizumab (2009), and pazopanib (2009).

Some of these medications and therapies may cause side effects, including diarrhea, high blood pressure, fatigue, decreased appetite, nausea, weakness, and vomiting. These should be discussed with a doctor or health care professional who can help you manage these symptoms.

Checkups and Self-Awareness May Help Catch Cancer Early

Although Sam Bhayani, MD, urologic surgeon at the Siteman Cancer Centerat Barnes-Jewish Hospital and Washington University School of Medicine in St. Louis, says most cases of kidney cancer have no symptoms and are found incidentally on a scan performed for other reasons, such as pain or blood in urine, recommended medical screenings may play a role in early detection. “Some cases present with blood in the urine, a mass on the side, or symptoms of pain.” Dr. Bhayani says. “Most cases are sporadic, and have unknown risk factors. Most cases have no identifiable risk factor, so they catch the patient by surprise.” However, if you have a strong family history of kidney cancer or an inherited disorder, such as von Hippel-Lindau disease, you should discuss your screening options with your doctor.