Kidney cancer is the 7th leading cause of cancer in men, and the 9th leading cause of cancer in women, in the United States. Most kidney cancers are discovered incidentally during an imaging study of the abdomen for some unrelated reason. Occasionally, kidney cancers are discovered because of symptoms related to the tumor. Symptoms may include blood in the urine, flank pain, abdominal pain, or weight loss. Usually the development of kidney cancer is random, though there are some heritable forms of the disease, and some risk factors.
- Age: adults in their 50s and 60s are more likely than other age groups
- Sex: men are twice as likely as women to get kidney cancer
- Race: African-Americans are more likely than Caucasians
- Industrial exposures: asbestos, organic solvents, certain heavy metals
- Genetics: von Hippel Lindau; papillary kidney cancer
The diagnosis is made by x-ray images, usually by CAT scan, and sometimes by MRI or ultrasound. Taking all comers, approximately 85% of kidney tumors are malignant (cancerous). The other 15% are considered benign. The larger the tumor, the more likely it is to be malignant. Definitive diagnosis is made pathologically by tumor removal. Biopsy is generally not recommended for these tumors because the small specimens often lead to a misdiagnosis, or false reassurance that there is not a cancer.