What is testicular cancer?

Cancer that develops in a testicle is called testicular cancer or cancer of the testis (plural: testes). Usually only one testicle is affected, but in some cases both are affected. About 90–95% of testicular cancers start in the cells that develop into sperm – these are known as germ cells.

Sometimes testicular cancer can develop outside the testicle. It can also spread to lymph nodes in the abdomen or to other parts of the body.

What types are there?

The most common testicular cancers are called germ cell tumours. There are two main types, seminoma and non-seminoma.

Sometimes a testicular cancer can include a mix of seminoma cells and non-seminoma cells, or a combination of the different subtypes of non-seminoma cells (mixed tumours). When there are seminoma and non-seminoma cells mixed together, doctors treat the cancer as if it were a non-seminoma cancer.

A small number of testicular tumours start in cells that make up the supportive (structural) and hormone-producing tissue of the testicles. These are called stromal tumours. The two main types are Sertoli cell tumours and Leydig cell tumours. They are usually benign and are removed by surgery.

Intratubular germ cell neoplasia (ITGCN)

Some testicular cancers begin as a condition called intratubular germ cell neoplasia (ITGCN or IGCN). In this condition, the cells are abnormal, but they haven’t spread outside the area where the sperm cells develop.

ITGCN is not cancer but it has about a 50% risk of turning into testicular cancer within five years. About 5–10% of men diagnosed with testicular cancer have ITGCN.

ITGCN has similar risk factors to testicular cancer. It is hard to diagnose because there are no symptoms and it can only be found by testing a tissue sample.

Once diagnosed, some cases of ITGCN will be carefully monitored (surveillance). Other cases will be treated with radiation therapy or with surgery to remove the testicle.

How common is it?

Testicular cancer is not a common cancer, but it is the second most commonly diagnosed cancer, after skin cancer, among young men aged 20–39. In Australia, about 850 men are diagnosed with testicular cancer each year, accounting for about 1% of all cancers in men. It occurs most often in men aged 25–40.

Anyone with a testicle can get testicular cancer. Transgender women, male-assigned non-binary people or intersex people can also get testicular cancer if they have a testicle. For information specific to your situation, speak to your doctor.