Kidney cancer is a type of cancer that occurs in the cells of the kidney. Kidney cancer is caused by the rapid abnormal overgrowth of cells within the kidney. Our bodies are always making new cells: so we can grow, to replace worn-out cells, or heal damaged cells after injury.
This process is controlled by certain genes and all cancers are caused by changes to these genes. Changes to our genes usually happen during our lifetime, although a small number of people inherit such a change from a parent.
As with all cancers, kidney cancers begin small and grow larger over time. Kidney cancers usually grow as a single mass but more than one tumour may occur in one or both kidneys.
These lumps can be benign (not cancerous) or malignant (cancerous). Benign lumps do not spread to other parts of the body.
When it first develops, a malignant tumour is confined to its original site. If cancer is treated in its early stages, the outcome can be positive. If these cells are not treated, they may spread into surrounding tissue and to other parts of the body. When these cells reach a new site they may continue to grow and form another tumour at that site.
Has not spread to the kidney from somewhere else. It is mostly a disease seen in adults over 40.
Secondary cancers or “metastases”
Is cancer that has spread from somewhere else in the body.
The average age of people found to have kidney cancer is 55 years. The disease is rare in children.
What are the risk factors?
Some factors that may increase the risk of developing kidney cancer include:
Smoking: People who smoke have almost double the risk of developing kidney cancer as non-smokers and may be associated with up to one third of all cases. This risk decreases if the person stops smoking.
Gender: Men are at higher risk of developing kidney cancer than women.
Obesity: Being very overweight or obese appears to be associated with an increased risk of developing kidney cancer in both men and women. It is thought that excess body fat may cause changes in certain hormones that can lead to kidney cancer:
- a high caloric diet – can increase the risk for kidney cancer
- lack of physical exercise – people who are not physically active have a higher risk to develop kidney cancer
Long-term dialysis and acquired cystic disease: People with advanced kidney disease have a higher risk of developing kidney cancer. Dialysis patients who develop cystic disease of the kidneys are at increased risk for kidney cancer. The estimated risk of kidney cancer amongst this group is 30 times greater than the general population. Men (ratio 7:1) and people with large cysts in large kidneys appear to be at significantly increased risk of developing kidney cancer, which tends to occur after 8-10 years of dialysis.
High blood pressure or hypertension: High blood pressure or hypertension has been found to be a risk factor for kidney cancer, independently to obesity and smoking.
Occupational exposure to toxic compounds: People regularly exposed to certain substances including: asbestos, lead, cadmium, dry-cleaning solvents, herbicides, benzene or organic solvents and petroleum products, as well as people who work in the iron and steel industries may have an increased risk of kidney cancer.
Family history of kidney cancer: People who have family members with kidney cancer, especially a sibling, are at increased risk. This may be because there may be abnormalities in their genes.
Genetic and hereditary conditions
- Von Hippel-Lindau (VHL) Disease
A rare inherited disorder caused by a VHL gene, in which blood vessels grow abnormally in the eyes, brain, spinal cord, adrenal glands, or other parts of the body.
- Hereditary Papillary Renal Cell Carcinoma
People that suffer from this condition have a hereditary tendency to develop one or more papillary renal cell carcinomas.
- Birt-Hogg-Dube Syndrome
An inherited condition in which benign tumours develop in hair follicles on the head, chest, back, and arms.
- Hereditary Leiomyomatosis Renal Cell Carcinoma Syndrome
A medical condition where fibrous tumours develop within the uterus and skin.
- Hereditary Renal Oncocytoma
An inherited medical condition characterized by the tendency to develop a benign type of kidney tumour – oncocytoma – with a low potential of becoming malignant.
- Polycystic Kidney Disease (PKD)
An inherited condition where grape-like clusters of fluid-filled cysts develop in both of the kidneys causing chronic kidney failure and end-stage kidney disease. Having PKD also increases the risk for kidney disease.
Kidney Cancer Support Service – 1800 454 363 – or email firstname.lastname@example.org if you have questions about kidney cancer