Types and grades of kidney cancer

The type of kidney cancer tells your doctor what sort of kidney cell it started in. The grade tells them how much the cancer cells look like normal cells. Knowing about the type and grade of kidney cancer helps your doctor decide which treatment you need.

Renal cell cancer

Renal cell cancer is also called renal cell adenocarcinoma. It is the most common type of kidney cancer in adults. Around 80 out of 100 kidney cancers (around 80%) are renal cell cancers. 

Renal cell cancer starts in cells in one of the nephrons inside the kidney. Nephrons filter the blood and make urine. Each kidney has between 1 and 2 million nephrons.

Main types

There are different types of renal cell cancer. The main types are:

• clear cell - between 70 and 80 out of 100 renal cell cancers (between 70% and 80%)
• papillary - between 5 and 10 out of 100 renal cell cancers (between 5% and 10%)
• chromophobe - between 3 and 5 out of 100 renal cell cancers (between 3% and 5%)

Sarcomatoid renal cell cancer

Around 5 out of 100 renal cell cancers (around 5%) have sarcomatoid features. This means that some of the cancer cells look like sarcoma cells under a microscope. Sarcomatoid renal cell cancer tends to grow quicker than other types of renal cell cancer. And it is more likely to be diagnosed at an advanced stage.

The symptoms and treatment of sarcomatoid kidney cancer are the same as for the others types of renal cell cancer. 

Rare types

Rare types of renal cell cancer include:

• cancer of the collecting duct
• renal medullary cancer - this is also called SMARCB1-deficient renal medullary carcinoma 

Upper urinary tract urothelial cancer

Upper urinary tract urothelial cancer used to be called transitional cell cancer (TCC) of the kidney or ureter. It starts in cells called transitional cells.

Transitional cells can change shape and stretch. They line the renal pelvis and ureter. The renal pelvis is the area of the kidney where urine collects. The urine then moves into the ureter and down to the bladder.

Sarcoma of the kidney

Sarcoma of the kidney is a rare type of soft tissue sarcoma. This means the cancer started in the connective tissue of the kidney. Connective tissue includes muscles, nerves, fat, blood vessels and fibrous tissue.

The treatment for sarcoma of the kidney is different from the more common types of kidney cancer.

Wilms tumour

A type of kidney cancer called Wilms tumour (nephroblastoma) can affect children. This is different from kidney cancer in adults.

Cancer that has spread to the kidney (secondary cancer)

Sometimes cancer that has started elsewhere in the body can spread to the kidney. This can happen with lung, breast, bowel and some skin cancers for example. 

Cancers that have spread from somewhere else in the body are called secondary cancers. The cancer cells are the same as the first (primary) cancer. The treatment is also the same as for the primary cancer.

If you have cancer that has spread to the kidney, read the section about your primary cancer for information.

Grades of kidney cancer

The grade of a cancer means how much the cancer cells look like normal cells. It tells your doctor how the cancer might behave and what treatment you need.

Clear cell and papillary renal cell cancers are graded 1-4. Grade 1 is the lowest grade and grade 4 is the highest.

There is currently no agreed way to grade chromophobe renal cell cancer.

To find out the grade of a cancer, a specialist (pathologist) looks at the cells under a microscope. They look at changes to the centre of the cell (nucleus).

The more the cancer cells look like normal kidney cells, the lower the grade. Low grade kidney cancers tend to grow more slowly. They are less likely to spread to another part of the body (metastasise).

The less the cancer cells look like normal kidney cells, the higher the grade. High grade kidney cancers tend to grow quicker. They are more likely to spread to another part of the body. 

The main factor for deciding on treatment is whether the cancer has spread away from the kidney or not. This is the stage of the kidney cancer.