Causes of testicular cancer
The exact cause or causes of testicular cancer are unknown, but a number of factors have been identified that increase a man's risk of developing it. The three main risk factors are described below.
Undescended testicles
Undescended testicles (cryptorchidism) is the most significant risk factor for testicular cancer.
Around 3 to 5% of boys are born with their testicles inside their abdomen. They usually descend into the scrotum during the first year of life, but in some boys the testicles don't descend.
In most cases, testicles that don't descend by the time a boy is a year old descend at a later stage. If the testicles don't descend naturally, an operation known as an orchidopexy can be carried out to move the testicles into the correct position inside the scrotum.
It's important that undescended testicles move down into the scrotum during early childhood because boys with undescended testicles have a higher risk of developing testicular cancer than boys whose testicles descend normally. It's also much easier to observe the testicles when they're in the scrotum.
Men with undescended testicles are about three times more likely to develop testicular cancer than men whose testicles descend at birth or shortly after.
Family history
Having a close relative with a history of testicular cancer or an undescended testicle increases your risk of also developing it.
For example, if your father had testicular cancer, you're around 4 times more likely to develop it than someone with no family history of the condition. If your brother had testicular cancer, you're about 8 times more likely to develop it.
Current research suggests a number of genes may be involved in the development of testicular cancer in families where more than one person has had the condition. This is an ongoing area of research in which patients and their families may be asked to take part.
Previous testicular cancer
Men who've previously been diagnosed with testicular cancer are between 4 and 12 times more likely to develop it in the other testicle.
For this reason, if you've previously been diagnosed with testicular cancer, it's very important that you keep a close eye on the other testicle. Read What should my testicles look and feel like?
If you've been diagnosed with testicular cancer, you also need to be observed for signs of recurrence for between 5 and 10 years, so it's very important that you attend your follow-up appointments.
Cancer Research UK has more information about testicular cancer risks and causes.
Introduction 