Kidney cancer at a glance
- Kidney (renal) cancer results from the development of malignant cells in the tissue of the kidneys, the two organs that cleanse the blood and produce urine.
- Renal cell carcinoma is the most common type of kidney cancer.
- Risk factors for kidney cancer include cigarette smoking, obesity and hypertension.
- Kidney cancer symptoms largely go unnoticed until the tumor is physically noticeable and may include blood in urine, the presence of a palpable mass and pain.
- Surgery is the standard treatment option, but minimally or non-invasive treatment options are also available.
What is kidney cancer?
Kidney cancer, or renal cancer (renal is derived from renes the Latin word for kidney), is the development and abnormal growth of malignant cells in the tissue of the kidneys. The kidneys are two small organs that rest on the side of the spine and lower abdomen that filter the blood to remove waste, producing urine. 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 kidney cancer include transitional cell carcinomas, Wilms tumors and renal sarcomas.
Kidney cancer occurs most often in men age 50-70. When discovered early, it carries a high survival rate of around 80 percent in the first five years after treatment with surgery.
The four stages of renal cancer are:
- Stage I – Consists of a tumor under 7 cm in size that remains only in the kidney.
- Stage II – The tumor is larger than 7 cm but remains only in the kidney.
- Stage III – The tumor exists in the kidney, the kidney’s main blood vessel, and fatty tissue around the kidney or extends into surrounding veins as well as the nearby lymph nodes.
- Stage IV – The tumor has spread from the kidney to the fatty tissue surrounding the kidney as well as lymph nodes.
In later stages, cancer may spread to other areas such as the bones, lungs and brain.
Causes of kidney cancer
Causes of kidney cancer can be related to environmental, occupational, cellular and genetic factors. Identified risk factors that may increase the likelihood of kidney cancer include:
- Older age
- Smoking cigarettes
- Being male
- Family history of kidney cancer.
Evidence of other risk factors may also be related to physical activity, alcohol consumption and occupational exposure to trichloroethylene. Genetic factors can also increase the risk.
A risk factor only suggests a correlation and does not exclusively determine whether one will get kidney cancer. Conversely, not having a risk factor also doesn’t mean one will not get the cancer.
Early stage kidney cancer usually doesn’t present any recognizable symptoms. When the cancer advances symptoms include:
- Blood in the urine
- A mass or persistent pain in the flank (the area on each side of the abdomen)
- Unexplained weight loss
- Chronic fever
- Abdominal and ankle swelling.
If kidney cancer spreads to other parts of the body, the patient’s bones may begin to ache and their breath will shorten. If a patient begins to cough up blood, this is also a sign that the cancer has spread. Neurologic symptoms may accompany the development of brain metastases.
Once symptoms are identified a doctor will perform further evaluation and recommend tests to diagnose the problem. Clinical and radiographic evidence may be sufficient to establish a diagnosis but other tests and a biopsy may be necessary for confirmation and to correctly determine the stage of the disease in order to develop the recommendations for treatment.