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Testicular cancer

Risks and causes of testicular cancer

Your risk of developing cancer depends on many factors. Anything that can increase your risk of cancer is called a risk factor. 

We don't know what causes most cases of testicular cancer. But there are some factors that may increase your risk of developing it.  

Having one or more risk factors doesn't mean that you will definitely get testicular cancer. As testicular cancer is rare, the risk of developing it is small even if you do have any risk factors.

Undescended testicles (cryptorchidism)

In the , the testicles develop in a male baby's abdomen. They usually move down into the at birth or in the first 6 months of life. If they do not move down, it's called undescended testicles and can affect one or both testicles. It is corrected by surgery. This is often done around 18 months of age, but the timing of surgery can vary. 

There is an increased risk of testicular cancer in people with undescended testicles. The risk is greater:

  • where the condition isn’t corrected

  • if surgery takes place after puberty

Abnormal cells in the testicle (Germ cell neoplasia in situ or GCNIS)

Germ cell neoplasia in situ (GCNIS) means that there are abnormal cells in the testicle. It isn't cancer. There is no lump and usually no other symptoms. This used to be called carcinoma in situ, or CIS.

If left untreated, GCNIS can develop into cancer within 5 years in about 50 out of 100 (about 50%) of the men who have it.  

Doctors might find and diagnose GCNIS when you have a testicular biopsy to check for infertility.

Your doctor will discuss treatment for GCNIS with you. This may include surveillance or surgery. In some situations, you might have low dose radiotherapy.

Family history

Brothers or sons of men who have had testicular cancer have an increased risk of getting this cancer.

Some of the increase in risk is thought to be caused by changes in certain . We need more research to understand how these gene changes affect the risk of testicular cancer.

Previous testicular cancer

If you have had testicular cancer already, there is a small increased risk of developing cancer in the other testicle.

It is important to attend follow up appointments after treatment.

Monitoring (surveillance) after a testicle is removed

Hypospadias

Men who are born with an abnormality of the penis and have an increased risk of developing testicular cancer. This is called hypospadias. It is a condition where the opening of the urethra is not at the end of the penis but somewhere else along the penis. It is usually identified at birth and is treated by surgery.

HIV

People with or AIDS have an increased risk of testicular cancer. But most cases of testicular cancer are not linked to being HIV positive.

You usually have antiviral drugs to treat HIV/AIDS. Some evidence suggests that these drugs cancel the increased risk linked with the infection.

Ethnic background

In the UK, white men have a higher risk of testicular cancer than men from other ethnic groups.

Are there other causes?

Stories about possible cancer causes are often in the media and it can be hard to know what’s true and what’s not. You may have heard of something that isn’t included here. This is because we only include a risk factor in this information if it is supported by good quality evidence.

Find out about common cancer myths and questions on the causes of cancer

Reducing your risk

There are ways you can reduce your risk of cancer.

Find out more about reducing your risk

More information about testicular cancer risks and causes

We have more detailed information for health professionals about testicular cancer risks and causes.

For detailed information go to the Cancer Statistics section

Last reviewed: 17 Mar 2025

Next review due: 17 Mar 2028

What is testicular cancer?

Testicular cancer is cancer that develops in the testicles. The testicles are part of the male reproductive system.

Types of testicular cancer

Your type of testicular cancer depends on which type of cell it started in. Knowing your type helps the doctor decide which treatment you need.

Symptoms of testicular cancer

Symptoms of testicular cancer include a lump or swelling in part of one testicle or a heavy scrotum. Find out about other possible symptoms and when you should see your GP.

Getting diagnosed with testicular cancer

You usually start by seeing your GP. They might refer you for tests or to a specialist if you have symptoms that could be caused by testicular cancer.

Treatment for testicular cancer

You usually have surgery. You might have chemotherapy or radiotherapy. This depends on the stage and type of your testicular cancer.

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