There are four types of kidney cancer, including renal cell carcinoma, transitional cell carcinoma, Wilm's tumor, and renal sarcoma. There are also benign (non-cancerous) kidney tumors. In adults, the most common type of kidney cancer is renal cell carcinoma; in children, it is Wilms’ tumor.
Read more about the stages of kidney cancer and recurrent kidney cancer.
Renal cell carcinoma (RCC), which accounts for about 90 percent of kidney cancers, arises from the lining of the tiny tubules inside the kidney that filter the blood and make urine. Although RCC usually grows as a single mass (tumor) within a kidney, occasionally there are two or more tumors in one kidney or even tumors in both kidneys at the same time. There are several subtypes of RCC, including:
- Clear cell is the most common form of renal cell carcinoma, affecting about 70 percent of people with RCC. It is associated with von Hippel-Lindau syndrome. It can be slow growing (grade I) up to fast growing (grade IV). Biologic therapies (immunotherapies) are most effective for this type.
- Papillary kidney cancer accounts for about 10 percent of RCC cases and is the second most common subtype. It is further divided into two different types and is associated with Hereditary Papillary RCC and Hereditary Leiomyomatosis and RCC syndromes.
- Collecting duct renal cell carcinoma is very rare and is usually treated with chemotherapy.
- Chromophobe renal cell carcinoma is also rare, accounting for about five percent of RCC cases. Birt-Hogg-Dube syndrome, a specific genetic mutation, is associated with chromophobe RCC.
- Unclassified renal cell carcinomas don’t fit into any of the other categories or may have more than one type of cell present. They often include aggressive tumors that don’t respond well to traditional therapies for RCC.
Transitional cell carcinomas account for five to 10 percent of all kidney cancers. Also known as urothelial carcinoma, this type of cancer does not start in the kidney, but in the renal pelvis (where the urine goes before it enters the ureter). For more information about transitional cell carcinoma see our bladder cancer section.
Wilm's tumor, also known as nephroblastomas, almost always occurs in children. For information about Wilm's tumor see the kidney tumor section on the Seattle Children's website.
Renal sarcoma is the most rare kidney cancer and accounts for just one percent of all kidney cancer cases. Renal sarcoma is treated like other sarcomas.
There are also three types of benign (non-cancerous) kidney tumors:
- Renal adenoma
- Oncocytoma, a benign (non-cancerous), slow-growing tumor that rarely spreads
- Angiomyolipoma, a benign tumor that can be removed surgically
Kidney cancer cells can spread by breaking away from the primary kidney tumor. They can travel through lymph vessels to nearby lymph nodes. They can also spread through blood vessels to the lungs, bones, or liver.
Staging is based on the size of the kidney tumor and how far the cancer has spread. If it is has spread to another part of the body, it is known as stage IV or metastatic kidney cancer. Treatment and eventual prognosis, or outlook on the success of your treatment, depends to a large extent on the cancer's stage.
Staging is based on the results of the physical exam, biopsies, and imaging tests (CT scan, MRI scan, chest X-ray).
There are two types of staging for kidney cancer. The clinical stage is your doctor's best estimate of the extent of your disease, based on the results of the physical exam, lab tests, and any imaging studies you have had.
If you have surgery, your doctors can also determine the pathologic stage, based on the same factors as the clinical stage, plus what is found during surgery and examination of the removed tissue.
Kidney cancers are staged as follows:
The tumor is less than 7 cm (2¾ inches) in greatest dimension and limited to the kidney; 5-year survival is nearly 95 percent.
The tumor is larger than 7 cm (about the size of a tennis ball) in greatest dimension and limited to the kidney; 5-year survival is approximately 75 percent.
The tumor can be any size; it has spread beyond the kidney to surrounding tissues and may have spread to regional lymph node(s); it is in major veins or adrenal gland and within the fibrous tissue surrounding the kidney and adrenal gland (Gerota’s fascia); 5-year survival is approximately 50 percent.
The tumor has spread outside the kidney and beyond Gerota’s fascia; or it has spread to multiple lymph nodes or to distant parts of the body, such as the bones, brain, liver, or lungs; 5-year survival is about 10 percent.
Recurrent Kidney Cancer
Despite treatment, kidney cancer may come back. Cancer that comes back after treatment is called recurrent cancer. Recurrence may be local (in or near the place it started) or distant (spread to organs, such as lung or bones). If the cancer reappears in other parts of the body, it is metastatic kidney cancer.