The type of kidney cancer you have tells you what type of cell it started in. Knowing this helps your doctor decide which treatment you need.
Renal cell cancer
Renal cell cancer is the most common type of kidney cancer in adults. It is also called renal cell adenocarcinoma. More than 8 out of 10 (80%) of kidney cancers are renal cell cancers.
In renal cell cancer, the cancerous cells start in the lining of the tubules (the smallest tubes inside the nephrons). Tubules help filter the blood and make urine.
The main types of renal cell cancer:
- clear cell - around 75 out of 100 renal cell cancers (75%)
- papillary - around 15 in 100 renal cell cancers (15%)
- chromophobe renal cell cancer - around 5 in 100 renal cell cancers (5%)
Rare types of renal cell cancer include carcinoma of the collecting ducts and renal medullary carcinoma. Sometimes kidney cancers can contain more than one cell type.
Another rare type is sarcomatoid. This means the kidney cancer cells look like sarcoma cells under the microscope. Sarcoma is cancer of connective tissue (such as muscles, nerves, fat, blood vessels, and fibrous tissues). Kidney cancer that is sarcomatoid type might have a different outlook to other types of kidney cancer.
Transitional cell cancer of the kidney or ureter
Transitional cell cancer means the cancer cells started in the transitional cells lining the renal pelvis or ureter. The renal pelvis is the central area of the kidney where urine collects before it goes down the ureter to the bladder.
The treatment for this type of kidney cancer is similar to the treatment for bladder cancer.
A type of kidney cancer called Wilms' tumour can affect children. This is different from kidney cancer in adults.
Grades of kidney cancer
Grade means how much the cancer cells look like normal cells. A specialist (pathologist) looks at the cells under a microscope. The pathologist will look at the centre of the cell (nucleus) and the size and shape of the cells.
The more the cancer cells look like normal cells, the lower the grade. They tend to grow more slowly and are less likely to spread to another part of the body (metastasise).
The less the cancer cells look like normal cells, the higher the grade. They tend to grow more quickly and are more likely to spread to another part of the body.
Kidney cancers are graded 1-4. This is called the Fuhrman system. Grade 1 is the lowest grade, and grade 4 is the highest grade.
The grade tells your doctor how the cancer might behave and what treatment you need. The main factor for deciding on the best treatment is whether your cancer has spread away from the kidney or not.