Find out about the causes of testicular cancer and how you can reduce your cancer risk.
In the UK around 2,300 men are diagnosed with testicular cancer each year. That's about 1 out of every 100 cancers (1%) diagnosed in men.
We don't know what causes most testicular cancers. But some factors can increase your risk of getting it.
What a risk factor is
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 get that cancer.
As testicular cancer is rare, the risk of developing it is small even if you do have any risk factors.
Risk factors for testicular cancer
The most important risk factor for testicular cancer is undescended testicles (cryptorchidism).
In the womb, the testicles develop in a male baby's abdomen. They usually move down into the scrotum at birth or in the first year of life.
If they move down later or need surgery to bring them down, they are called undescended testicles.
In most men the testicles move down by the age of puberty. Some men have surgery to bring them down.
- Having undescended testicles increases the risk of getting testicular cancer by 3 times
- In men where the condition is not corrected by the age of 13, the risk of testicular cancer increases by up to 6 times
Carcinoma in situ (CIS) means that there are abnormal cells in the testicle. It isn't cancer. There is no lump and usually no other symptoms.
These abnormal cells are completely contained. Unlike cancer cells they can't spread. If left untreated CIS develops into cancer in about half (50%) the men who have it.
CIS is most often found when a man has a testicular biopsy to check for infertility.
It can be treated by removing the testicle to prevent testicular cancer from developing.
Men with fertility problems have an increased risk of testicular cancer.
The key problems are:
- low semen concentration
- sperm that does not move around as much as normal
- a high proportion of abnormal sperm
We are still not sure why fertility problems and testicular cancer are linked.
It may be because testicular cancer and fertility problems share some of the same risk factors.
If you have had testicular cancer already, your risk of developing a cancer in the other testicle is increased by 12 times.
It is important to attend follow up appointments after treatment.
Brothers or sons of men who have had testicular cancer have an increased risk of getting it.
- Men whose father had testicular cancer are around 4 times more likely to develop it
- Men with a brother who had testicular cancer are around 8 times more likely to develop it
Some of the increase in risk is caused by changes in certain genes. Further research could lead to a test that identifies men at a higher risk of testicular cancer.
Men who have family members with non-Hodgkin lymphoma and oesophageal cancer have an increased risk of testicular cancer.
Men who are born with an abnormality of the penis and urethra called hypospadias are more likely to develop testicular cancer.
Men who have an inguinal hernia are more likely to develop testicular cancer.
An inguinal hernia is a lump in the groin area caused by a part of the bowel (intestine) slipping through a weakness in the tummy (abdominal) wall.
Men with HIV or AIDS have an increased risk of testicular cancer. But most cases of testicular cancer are not linked to being HIV positive.
Testicular cancer is more common in some racial and social groups.
In the US, more than 4 times as many white men than black men get testicular cancer
In the UK, white men have a higher risk of testicular cancer than men from other ethnic groups
We don't know why this is.
Calcium specks in the testicles (testicular microlithiasis) are often found by chance. Doctors usually diagnose this with an ultrasound scan when checking testicular symptoms such as pain or swelling.
It is difficult to know how many men have it. It may affect between 2 and 6 out of every 100 men (2% to 6%).
For men who have it, there is no direct increase in risk of getting testicular cancer. But men who have it along with other testicular cancer risk factors (such as fertility problems or undescended testicle) have an increased risk.
There are no guidelines on how your doctor should monitor you if you have calcium specks in the testicle. Your GP should talk the situation through with you. Then you can both make a decision based on what is best in your case.
If you have calcium specks and notice any swelling in your testicle, see your doctor straight away.
Men who are taller than average have an increased risk of testicular cancer.
There is no known link between injury or sporting strains and testicular cancer. But an injury often causes swelling and lumps in the testicle, which can make a tumour difficult to spot.
If you have had a testicular injury and have any swelling, go to your GP for a check up.
Between the 1940s and early 1970s, doctors used to prescribe a drug called diethylstilbestrol (DES) to some pregnant women with a history of pregnancy problems. There has been a lot of research to see if exposure to DES in the womb increases the risk of testicular cancer. But a meta-analysis of the research didn't find a significantly higher incidence of testicular cancer in DES exposed boys. There is a higher frequency of undescended testicle in boys born to DES mothers. Undescended testicle is a risk factor for testicular cancer, so there could be an indirect link.
Men whose mothers had bleeding during pregnancy have a higher risk of testicular cancer. But men who have older brothers and sisters have a lower risk.
A low birth weight can increase the risk of an undescended testicle. But it is unclear whether birth weight directly affects testicular cancer risk.
Twins have an increased risk of testicular cancer, especially if they are both boys. But as testicular cancer is so rare the risk is still low.
There is no known link between vasectomy and testicular cancer.
Early research suggested a link, but this has since been shown to be untrue.
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.
Reducing your risk
Find out about about ways of reducing your risk of cancer.