Kidney Cancer Information
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What is Kidney Cancer?
Kidney cancer occurs when a malignant tumor forms in the tissue of the kidney. The kidneys are a pair of bean-shaped organs located on either side of the spine, protected by the lower ribcage. Their main function is to filter blood and remove excess water, salt and waste from the body. Although the body has two kidneys, only part of one kidney is necessary to function.
According to the American Cancer Society, over 58,000 people were diagnosed with kidney cancer in 2010. The risk of developing kidney cancer is 1 in 67 people, with men having a higher risk than women.
Types of Kidney Cancer
Renal cell carcinoma (RCC) is the most common type of kidney cancer. The cancerous cells typically develop in the lining of very small tubes in the kidney, called tubules. Over time, these cells may grow into a mass and cause an obstruction. The cancer may form in one or both of the kidneys.
Subtypes of Renal Cell Carcinoma
- Clear Cell RCC accounts for approximately 80 percent of all renal cell carcinomas. The tumor cells appear very pale or clear when observed under a microscope.
- Papillary RCC is the second most common type of RCC and accounts for 10-15 percent of kidney cancers. The cancerous cells develop finger-like projections in the tumor.
- Chromophobe RCC, like clear cell RCC, has tumor cells that appear pale or clear under a microscope. However, cells related to this type of cancer tend to be larger in size.
- Collecting Duct RCC is a rare and aggressive type of RCC, accounting for less than one percent of kidney cancers. The cancerous cells form irregular tubes inside the tumor.
- Unclassified RCC is another rare type of kidney cancer. These cells cannot be classified based on their appearance under a microscope. Alternately, cancers that have more than one subtype may be grouped in this category.
Other Cancerous Kidney Tumors
- Transitional cell carcinoma develops in the region where the kidney and the ureters join. The ureters are tubes that carry urine from the kidneys to the bladder. The tumor cells may begin to look more like bladder cancer cells than kidney cancer cells when observed under a microscope. This cancer type may also be referred to as urothelial cancer or renal pelvis carcinoma.
- Renal sarcoma is a rare type of kidney cancer that develops in the connective tissue of the kidney.
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