Kidney cancer begins in the kidneys. Your kidneys are two bean-shaped organs, each about the size of your fist. They're located behind your abdominal organs, with one kidney on each side of your spine.

In adults, renal cell carcinoma is the most common type of kidney cancer — about 90 percent of cancerous tumors. Other less common types of kidney cancer can occur. Young children are more likely to develop a kind of kidney cancer called Wilms' tumor.

The incidence of kidney cancer seems to be increasing. One reason for this may be the fact that imaging techniques such as computerized tomography (CT) scans are being used more often. These tests may lead to the accidental discovery of more kidney cancers. In many cases, kidney cancer is found at an early stage, when the tumors are small and confined to the kidney, making them easier to treat.

Kidney cancer rarely causes signs or symptoms in its early stages. And currently there are no routine tests used to screen for kidney cancer in the absence of symptoms. In the later stages, kidney cancer signs and symptoms may include:

• Blood in your urine, which may appear pink, red or cola colored
• Pain in your back or side that doesn't go away
• Loss of appetite
• Unexplained weight loss
• Tiredness
• Fever, which usually comes and goes (intermittent)

When to see a doctor

Make an appointment with your doctor if you have any persistent signs or symptoms that worry you.

It's not clear what causes renal cell cancer, the most common form of kidney cancer, though there are several risk factors.

Doctors know that kidney cancer begins when some kidney cells acquire mutations in their DNA. The mutations tell the cells to grow and divide rapidly. The accumulating abnormal cells form a tumor that can extend beyond the kidney. Some cells can break off and spread (metastasize) to distant parts of the body.

Together, you and your treatment team can discuss your kidney cancer treatment options. The best approach for you may depend on a number of factors, including your general health, the kind of kidney cancer you have, whether the cancer has spread and your preferences for treatment.

Surgery

Surgery is the main treatment for the majority of kidney cancers, with the goal of removing the tumor and preserving normal kidney function. Surgical procedures used to treat kidney cancer may include:

• Removing the affected kidney (nephrectomy). A complete (radical) nephrectomy involves removing the entire kidney, a border of healthy tissue and occasionally additional nearby tissues such as the lymph nodes, adrenal gland or other structures. The surgeon may perform a nephrectomy through a single incision in the abdomen or side (open nephrectomy) or through a series of small incisions in the abdomen (laparoscopic or robotic-assisted laparoscopic nephrectomy).
• Removing the tumor from the kidney (partial nephrectomy). Also called kidney-sparing or nephron-sparing surgery, the surgeon removes the tumor and a small margin of healthy tissue that surrounds it rather than the entire kidney. It can be done as an open procedure, or laparoscopically or with robotic assistance. Kidney-sparing surgery is a common treatment for small kidney cancers and it may be an option if you have only one kidney. When possible, kidney-sparing surgery is generally preferred over a complete nephrectomy to preserve kidney function and reduce the risk of later complications, such as kidney disease and the need for dialysis.

The type of surgery your doctor recommends will be based on your cancer and its stage, as well as your health. Surgery carries a risk of bleeding and infection.

When the cancer is confined to the kidney, surgery is usually the only treatment needed — no drugs or radiation are necessary. Routine follow-up is all that's needed.

Nonsurgical treatments

For some people, alternative options are available to destroy small tumors without surgery. These options include:

• Treatment to freeze cancer cells (cryoablation). During cryoablation, a special hollow needle is inserted through your skin and into the kidney tumor using ultrasound or other image guidance. Cold gas in the needle is used to cool down or freeze the cancer cells.
• Treatment to heat cancer cells (radiofrequency ablation). During radiofrequency ablation, a special probe is inserted through your skin and into the kidney tumor using ultrasound or other imaging to guide placement of the probe. An electrical current is run through the needle and into the cancer cells, causing the cells to heat up or burn.

These procedures may have advantages for certain patients and are a potential option for people who can't have other surgical procedures and those with small kidney tumors.

Treatments for advanced and recurrent kidney cancer

Kidney cancer that recurs and kidney cancer that spreads to other parts of the body may not be curable, but may be controlled with treatment. In these situations, treatments may include:

• Surgery to remove as much of the kidney tumor as possible. Even when surgery can't remove all of your cancer, in some cases it may be helpful to remove as much of the cancer as possible. Surgery may also be used to remove cancer that has spread to another area of the body.
• Drugs that use your immune system to fight cancer (biological therapy). Biological therapy (immunotherapy) uses your body's immune system to fight cancer. Drugs in this category include interferon and aldesleukin (Proleukin), which are synthetic versions of chemicals made in your body. Nivolumab (Opdivo) is an immunotherapy sometimes used to treat advanced renal cell carcinoma.
• Targeted therapy. Targeted treatments block specific abnormal signals present in kidney cancer cells that allow them to multiply. These drugs show promise in treating kidney cancer that has spread to other areas of the body. The targeted drugs cabozantinib (CaboMetyx), axitinib (Inlyta), bevacizumab (Avastin), pazopanib (Votrient), sorafenib (Nexavar) and sunitinib (Sutent) block signals that play a role in the growth of blood vessels that nourish cancer cells and allow them to spread. Temsirolimus (Torisel) and everolimus (Afinitor) are targeted drugs that block a signal that allows cancer cells to grow and survive. Researchers continue to study how patients with specific genes might respond to certain targeted therapies.
• Radiation therapy. Radiation therapy uses high-powered energy beams, such as X-rays, to kill cancer cells. Radiation therapy is sometimes used to control or reduce symptoms of kidney cancer that has spread to other areas of the body, such as the bones and brain.
• Clinical trials. Depending on your type of tumor, cancer stage and prognosis, your doctor may inform you of relevant clinical research trials. Some clinical trials assess the safety and effectiveness of potential treatments. Other clinical trials try to find new ways to prevent or detect disease.

Be sure to thoroughly discuss with your doctor the benefits, risks and possible side effects of any treatment that you're considering.

Factors that can increase the risk of kidney cancer include:

• Older age. Your risk of kidney cancer increases as you age.
• Smoking. Smokers have a greater risk of kidney cancer than nonsmokers do. The risk decreases after you quit.
• Obesity. People who are obese have a higher risk of kidney cancer than people who are considered average weight.
• High blood pressure (hypertension). High blood pressure increases your risk of kidney cancer.
• Treatment for kidney failure. People who receive long-term dialysis to treat chronic kidney failure have a greater risk of developing kidney cancer.
• Certain inherited syndromes. People who are born with certain inherited syndromes may have an increased risk of kidney cancer, such as those who have von Hippel-Lindau disease, Birt-Hogg-Dube syndrome, tuberous sclerosis complex, hereditary papillary renal cell carcinoma or familial renal cancer.
• Family history of kidney cancer. Even in the absence of an inherited syndrome, people who have a strong family history of renal cell cancer have a greater risk of kidney cancer.
• Exposure to certain substances in the workplace.This might include, for example, exposure to cadmium or specific herbicides.