We don't know what causes most kidney cancers. But some factors may increase your risk of getting it.
What is a risk factor?
Anything that can increase your risk of getting a disease is called a risk factor.
Different cancers have different risk factors. Having one or more of these risk factors doesn't mean you will definitely get that cancer.
Risk factors for kidney cancer
Being overweight or very overweight (obese) increases the risk of getting kidney cancer. This causes 24 out of every 100 kidney cancers (24%). So around a quarter of kidney cancers.
Overweight means that your body mass index (BMI) is between 25 and 39.9 and obese means that your BMI is 30 or higher. Your BMI is worked out by using your height and weight.
Being overweight causes changes in hormones in the body, particularly for women. It could be this change in the body’s hormone balance that increases the risk of kidney cancer.
People who smoke have an increased risk of developing kidney cancer. This risk increases with the length of time and number of cigarettes that you smoke.
Your risk falls if you stop smoking. After 10 years it becomes nearly the same as those who have never smoked.
People with kidney failure have their blood filtered by a machine about twice a week. This is called dialysis. People having long term kidney dialysis have an increased risk of developing kidney cysts. This increases the risk of kidney cancer.
The longer you have dialysis, the greater your risk of kidney cancer. But this is probably because you needed dialysis due to kidney disease. The dialysis itself is not directly related to the cancer risk.
A few people inherit faulty genes that increase their risk of developing kidney cancer. Cancers caused by these faulty genes are called hereditary or familial kidney cancer.
Changes in the DNA that makes up the faulty gene make it behave in an abnormal way. Scientists are finding out which genes carry these mistakes in the DNA. In the future this could help doctors predict who is at risk of getting hereditary kidney cancer.
People with kidney cancer who have these genetic conditions often have cancer in both kidneys (bilateral kidney cancer). They may also have several tumours in each kidney. They often develop the cancer at a younger age than people with non inherited cancers.
Inherited conditions that increase the risk of kidney cancer
Von Hippel-Lindau (VHL) syndrome
This is an inherited cancer syndrome. The Von Hippel-Lindau (VHL) gene runs through affected families.
People who carry the gene have an increased risk of developing several quite rare cancers in the brain, spine, pancreas, eyes and inner ear.
This is another condition caused by a faulty gene. People with tuberous sclerosis have an increased risk of kidney cysts and kidney cancer.
It can cause skin, brain and heart problems, as well as kidney disease.
This inherited condition causes many non cancerous (benign) tumours to develop in the hair follicles of the skin. These usually develop on the face, neck and trunk. People who carry this gene have an increased risk of kidney cancer.
Hereditary clear cell and papillary renal cell cancer
Hereditary clear cell kidney cancer and hereditary papillary kidney cancers are both caused by inherited faulty genes. They are dominant genetic conditions. This means that you only have to inherit the faulty gene from one parent. Even so, they are both very rare.
People with a first degree relative who have been diagnosed with kidney cancer have roughly double the risk of developing renal cell carcinoma themselves. A first degree relative is your parent, brother or sister, or child.
Some research studies have found a link between high blood pressure or high blood pressure medicines and kidney cancer.
It is likely that high blood pressure is the link, rather than the medicines. High blood pressure is a known risk factor for kidney disease in general.
People who have had thyroid cancer have an increased risk of kidney cancer. This may be due to gene changes that are common to both cancers.
Some studies have found that people with diabetes type 1 have a higher risk of kidney cancer.
The risk may be higher in people who use insulin to control their diabetes. But other diabetic medicines such as metformin or pioglitazone don't seem to increase the risk.
Researchers in America looked at the results of 20 studies across 6 countries. They found that some mild painkilling drugs are linked to increased kidney cancer risk.
One drug that could definitely increase the risk was phenacetin, but this has been taken off the market in the UK.
Some other types of painkillers called non steroidal anti inflammatory drugs (NSAIDs) may increase the risk of kidney cancer slightly. These include ibuprofen. Occasional or low dose use is unlikely to be harmful.
Other possible causes
Stories about potential causes of cancer are often in the media. It isn’t always clear which ideas are supported by good evidence.
You might hear about possible causes we haven’t included here. This is because there is no evidence about them or because the evidence isn’t clear.