Kidney cancer affects men about twice as often as women. Most people who contract this disease are over the age of 50.
At this time, the causes of kidney cancer are not well understood. It can seldom be explained why one person gets this disease and another doesn't. Kidney cancer is not contagious; no one can "catch" any type of cancer from another person.
Although scientists do not know exactly why kidney cancer develops, they have learned that some things (risk factors) increase a person's chance of getting this disease. For example, we know that smoking is a major risk factor for kidney cancer. Smokers are twice as likely to get this disease as nonsmokers. Scientists think cigarette smoking causes more than one-fourth of all kidney cancers in the United States. People who smoke are also more likely to get cancers of the lung, mouth, throat, larynx (voice box), esophagus, bladder, and pancreas.
Some people have developed kidney cancer after heavy, long-term use of a pain-killing drug called phenacetin. This drug is no longer sold in the United States.
Several studies suggest that the risk of developing kidney cancer may be higher than average among people with certain jobs. Groups with increased risk include coke oven workers and those who work with asbestos. Scientists are trying to learn more about these workers, and they are studying other occupations as well.
Although scientists cannot yet explain why, research shows that being overweight can increase the chance of getting some types of cancer. Kidney cancer may be one of them. Maintaining ideal weight may reduce the risk of cancer and other diseases, including heart disease, diabetes, and high blood pressure.
What are the symptoms of kidney cancer?
The most common symptom of kidney cancer is blood in the urine. In some cases, a person can actually see the blood. It may be present one day and not the next. Traces of blood may also be found in urinalysis, a urine test done as part of a regular medical checkup.
Another symptom of kidney cancer is a lump or mass that can be felt in the kidney area. The tumor may cause a dull ache or pain in the back or side. Less often, signs of a kidney tumor include high blood pressure or an abnormal number of red blood cells.
Symptoms may develop suddenly. However, as with other types of cancer, kidney cancer can cause a general feeling of poor health. People with this disease may feel tired, lose their appetite, and lose weight. Some have a fever that comes and goes.
These symptoms may be caused by cancer or by other, less serious problems such as an infection or a fluid-filled cyst. A doctor is consulted for a definite diagnosis.