Kidney cancer at a glance
- Kidney cancer, also known as renal cancer, is caused by the development of malignant cells in the tissue of the kidneys.
- The three main types of kidney cancer are Wilms tumors (in children), transitional cell cancer and renal cell cancer, the most common by far.
- Symptoms largely go unnoticed until the tumor is physically noticeable, when patients may experience blood in urine, the presence of a palpable mass and pain.
- Oncologists do not know the exact cause of kidney cancer, but identified risk factors include cigarette smoking, obesity and hypertension, among others.
- Surgery is the standard option for kidney cancer treatment but minimally or noninvasive treatment options are also available.
Kidney cancer causes
Kidney cancer, also known as renal cancer (renes is Latin for kidney), occurs when cells in the tissue of the kidneys grow out of control and form malignant tumors. The two kidneys located next to the spine and above the waist filter waste from the blood into urine that passes to the bladder before being expelled from the body. Kidneys also control the production of red blood cells and produce hormones that help in the body’s regulation of blood pressure.
The most common type of kidney cancer in adults is renal cell carcinoma, which begins in the small tubes in the kidney that move waste from the blood into urine. Rarer forms of cancer of the kidney include transitional cell carcinomas, Wilms tumors that affect children and renal sarcomas.
According to the National Cancer Institute, kidney cancer is the 13th leading cause of cancer death in the United States and accounts for about 4 percent of all cancers. The American Cancer Society says it is the 10th most common cancer men and women. Kidney cancer occurs slightly more often in males than in females and is usually diagnosed between the ages of 50 and 70. But kidney cancer can occur at any age.
Doctors are unclear of what causes kidney cancer but they do know it begins when kidney cells start mutating in DNA. These mutations grow and divide at a rapid rate and form a cancerous tumor.
Kidney cancer stages
The stage of cancer explains how far the cancerous cells have spread and is based on different biopsies, physical exams and imaging tests (CT scan, PET scan).
The four stages of kidney cancer are:
Stage I – The primary cancer is 7 centimeters (about 3 inches) or less and limited to the kidney, with no spreading to lymph nodes or distant sites.
Stage II – Primary cancer is greater than 7 centimeters and limited to the kidney, with no spreading to lymph nodes or distant sites.
Stage III – The cancer has spread to the regional lymph nodes but not to distant sites in the body, and/or it extends to the renal veins or vena cava (large vein returning blood to the heart).
Stage IV – The cancer has spread to distant sites or invades directly beyond the local area.
Determining the extent of the spread or the stage of the cancer requires a number of tests. Staging tests include X-rays, computerized tomography (CT) scans, ultrasonography or magnetic resonance imaging (MRI). In later stages, cancer may spread to other areas such as the bones, lungs and brain.
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Having a risk factor, or even several risk factors, does not mean a person will get kidney cancer. Some people who get the disease may have few or no known risk factors. Even if a person with kidney cancer has a risk factor, it is often hard to determine how much that risk factor contributed to the cancer.
Risk factors of kidney cancer can be related to environmental, lifestyle, occupational, hereditary and genetic factors. Identified risk factors include:
- Being male – Men are twice as likely to have kidney cancer than women.
- Older age – Most people who get kidney cancer are over age 40.
- Smoking – The risk is twice as high for smokers as for nonsmokers.
- Obesity – Carrying extra weight may cause hormone changes that can increase cancer risk.
- Kidney disease – Receiving long-term dialysis for chronic kidney failure increases the risk of developing renal cancer.
- Family history – Siblings of people who have had this cancer have greater risk.
- High blood pressure (hypertension).
- Certain genetic conditions – People with certain conditions such as von Hippel-Lindau disease, Birt-Hogg-Dube syndrome, tuberous sclerosis and familial papillary renal cell carcinoma.
- Environmental – Exposure to certain chemicals such as asbestos, benzene, cadmium, and some herbicides and organic solvents.
Evidence of other risk factors may also be related to physical activity, alcohol consumption and occupational exposure to herbicides or organic solvents.
Kidney cancer symptoms
A lack of symptoms leads to many kidney tumors going undetected. Physicians often detect such tumors while conducting a test for something else. Symptoms of pain in the stomach area, pain in the back and visible blood in the urine occur when kidney tumors stretch or compress, as well as when they protrude against structures near the kidney or in it.
Other symptoms include:
- Loss of appetite
- Involuntary weight loss
- Ongoing fever
If kidney cancer spreads to other parts of the body, which is called metastasis, symptoms are generally specific to the area where it has spread. For example, kidney cancer that has spread to the lungs can cause shortness of breath, and blood can be coughed up.
Kidney cancer treatments
Kidney cancer treatment options depend on the kind of kidney cancer, the stage and the location of the cancerous cells. Surgery is the most common treatment option for the majority of kidney cancers. Surgical procedure options include the following.
This removes the affected kidney, a border of healthy tissue and the adjacent lymph nodes. This surgery can be an open operation done by making a large incision to access the kidney or can be done robotically with a robot and hand controls.
This procedure removes the tumor and a small section of healthy tissue that surrounds it, rather than removing the entire kidney. This surgery is common for small kidney cancers and is also an option if the patient only has one kidney. Nephron-sparing surgery, also called a partial nephrectomy, can be an open procedure or done via laparoscopy, which involves a tube with camera inserted through a small incision in the belly providing a video view of the area and allowing the surgeon to operate using special instruments.
Nonsurgical treatments for kidney cancer are considered when the patient cannot undergo surgery by choice or he or she isn’t a good candidate as determined by the oncologist. The treatment options for these patients are as follows.
- Radiation therapy – high-energy radiation delivered through external beam therapy.
- Targeted therapy – a type of drug that inhibits the growth of new blood vessels and blocks proteins in cancer cells that help them grow and survive.
- Immunotherapy – a way to boost the body’s immune system using cytokines, a group of natural proteins, to activate the immune system. Oncologists use immunotherapy for those who don’t respond to targeted drugs.
- Chemotherapy – anti-cancer drugs administered through a vein or by mouth that enter the blood stream to reach all areas of the body. This treatment is useful for cancer that has spread to organs outside the kidney.
- Sometimes more than one of type of treatment may be used if necessary. It’s important for patients to discuss treatment options and their possible side effects with their oncologist to help make the decision that best fits their needs.
When time permits, getting a second opinion is often a good idea. It can give patients more information and helps them feel good about the kidney cancer treatment plan they choose.