Risks and causes of kidney cancer

Kidney cancer is the 8th most common cancer diagnosed in men in the UK and the 9th most common cancer in women (excluding non melanoma skin cancer).  More than 8,700 people are diagnosed each year in the UK. Nearly 2 out 3 people diagnosed are over 65 years old. Kidney cancer is rare in people under 50. It is diagnosed more often in men than women. This could be because in the past more men smoked cigarettes. Smoking increases your risk of getting kidney cancer.

Obesity increases the risk of getting kidney cancer. A Cancer Research UK study published in 2011 found that being overweight or obese causes around a quarter of kidney cancers (25%). Obese means that your body mass index is over 30. Or more roughly, that your weight is at least 25% higher than the top of the range for your height. Body mass index (BMI) is worked out by comparing 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.

There is information about the right weight for you in CancerHelp UK. And information about healthy eating on our news and resources website.

If you smoke your risk of getting kidney cancer could be double that of a non smoker. The longer you continue to smoke and the higher the number of cigarettes you smoke, the higher the risk becomes. But if you stop smoking your risk of getting kidney cancer will probably fall.

People with kidney failure have to 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 and 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 small number of people inherit a faulty gene that increases their risk of developing kidney cancer. Changes in the DNA that makes up the gene make it behave in an abnormal way. This is called hereditary or familial kidney cancer. 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. For more information about these rare types of kidney cancer, look at the page for kidney cancer organisations.

The inherited conditions that greatly increase the risk of kidney cancer include

• Von Hippel-Lindau (VHL) syndrome
• Tuberous sclerosis
• Birt-Hogg-Dube syndrome
• Hereditary non vHL clear cell and papillary renal cell cancer

Von Hippel-Lindau (VHL) syndrome

Von Hippel-Lindau syndrome is an inherited cancer syndrome. The 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. About 40% of people with vHL get kidney cancer.

Tuberous sclerosis

Tuberous sclerosis (TS) is another condition caused by a faulty gene. About 1 in 3 cases are inherited. But the other 2 out of 3 occur because the gene has mutated in those people for the first time. It can cause skin, brain and heart problems, as well as kidney disease. People with TS have an increased risk of kidney cysts and kidney cancer.

Birt-Hogg-Dube syndrome

Birt-Hogg-Dube syndrome is another inherited condition. It causes many benign tumours to develop in the hair follicles of the skin. These usually develop on the face, neck and trunk. People that carry this gene are at 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.

Studies have shown that people with a first degree relative diagnosed with kidney cancer have roughly double the risk of developing it themselves. A first degree relative is a parent, brother or sister, or your child.

Apart from obesity, we aren't sure what part diet plays in kidney cancer. Eating large amounts of well cooked meat or having a high fat intake may increase the risk. People who eat enough fruit and vegetables may lower their risk of kidney cancer. At this point, there isn't enough evidence to say for sure. But following these sort of dietary guidelines can lower your risk of other cancers, as well as heart disease. So you certainly won't be doing yourself any harm if you improve your diet. The risk of kidney cancer is slightly lower in people who drink alcohol compared to non drinkers. However, alcohol increases the risk of several other cancers.

One study has shown that people with the hepatitis C virus have almost double the risk of developing kidney cancer compared to the general population.

Men treated with radiotherapy for testicular cancer have their risk of kidney cancer increased by almost three times, and women with a previous cancer of the neck of the womb (cervical cancer) have their risk increased by almost a third. But the risk is still small as kidney cancer is a rare cancer.

Some mild painkilling drugs have been 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. Other painkillers called non steroidal anti inflammatory drugs (NSAIDs), including ibuprofen (Nurofen), aspirin and paracetamol may increase the risk of kidney cancer slightly. Research into painkillers and kidney cancer risk is at a relatively early stage. It is unlikely that occasional use or low dose use would be harmful. For example, some studies have only found a slight link with regular use of paracetamol.

Some research studies have found a link between high blood pressure or high blood pressure medicines and kidney cancer. It is more 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.