Cancer that starts in the cells of a testicle is called testicular cancer or cancer of the testis (which means one testicle). Usually, it affects only one testicle, but sometimes both are affected.
As testicular cancer grows, it can spread to lymph nodes in the abdomen (belly) or to other parts of the body, such as other lymph nodes, lungs or liver. It does not spread to the other testicle.
Learn more about:
- What types are there?
- The testicles
- Who gets testicular cancer?
- What causes testicular cancer?
- Germ cell neoplasia in situ (GCNIS)
What types are there?
The most common testicular cancers are called germ cell tumours.
Germ cell tumours
There are 2 main types of germ cell tumours: seminoma and non-seminoma.
| seminoma |
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| non-seminoma |
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A testicular tumour can also include a mix of seminoma and non-seminoma cells, or a combination of the different types of non-seminoma cells. This is called a mixed germ cell tumour and is treated the same as 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 2 main types are Sertoli cell tumours and Leydig cell tumours. They are usually benign (not cancer) and are removed by surgery.
What is Germ cell neoplasia in situ (GCNIS)?
Most testicular cancers begin as a condition called germ cell neoplasia in situ (GCNIS). In GCNIS,
the cells are abnormal, but they haven’t spread outside the area where the sperm cells develop.
GCNIS is not cancer, but it may develop into cancer. GCNIS has similar risk factors to testicular cancer and is hard to diagnose because there are no symptoms. It can only be diagnosed by testing a tissue sample.
Some GCNIS cases will be carefully monitored (this is called active surveillance), while other cases will be treated with radiation therapy or surgery to remove the testicle.
Rarely, other types of cancer, such as lymphoma or neuroendrocrine tumours, can also involve the testicles. Call Cancer Council 13 11 20 for more information.
About the testicles
The testicles (also called testes) are part of the male reproductive system, which also includes the penis and prostate (see diagram right). They are 2 small egg-shaped glands that sit in the scrotum.
The testicles make and store sperm. They also make the hormone testosterone, which is responsible for the development of male characteristics, such as facial hair, a deeper voice and sex drive (libido).
The male reproductive system
*Not part of the male reproductive system
| Epididymis | a tube behind each testicle that stores immature sperm |
| Spermatic cord | contains blood vessels, nerves, lymph vessels and the vas deferens |
| Vas deferens | a long tube that carries mature sperm to the urethra to prepare for ejaculation |
| Scrotum | a pouch of skin that holds the testicles |
| Seminal vesicles | glands that produce fluid that carries sperm |
| Prostate | a gland that produces fluid that helps nourish and protect sperm |
| Urethra | a tube that runs from the bladder and through the prostate to take urine (pee) out of the body |
Who gets testicular cancer?
Testicular cancer is not common overall, but it is the most common cancer diagnosed in men aged 20–39 (apart from skin cancers). About 1026 people in Australia are diagnosed with testicular cancer each year, which is about 1% of all cancers in men.
Anyone with a testicle can get testicular cancer, including men, transgender women, non-binary people and people with intersex variations.
For information specific to you, speak to your doctor or see LGBTQI+ people and cancer.
What causes testicular cancer?
The causes of testicular cancer are largely unknown, but certain factors may increase your risk of developing it.
Talk to your doctor if you are concerned about any of the following risk factors:
- having germ cell neoplasia in situ (GCNIS)
- diagnosed with testicular cancer previously – if you previously had cancer in one testicle, you are slightly more at risk of developing cancer in the other
- undescended testicles – having undescended testicles at birth increases the risk
- family history – if your father or brother has had testicular cancer, you are slightly more at risk (2%) of developing testicular cancer
- infertility
- HIV or AIDS
- hypospadias – a condition when the opening of the urethra is on the underside of the penis. People born with this condition have a slightly higher risk of developing testicular cancer
- intersex variations – some types of intersex variations, such as partial androgen insensitivity syndrome, can increase the risk of developing testicular cancer. For more on this, see LGBTQI+ people and cancer.
→ READ MORE: Testicular cancer symptoms
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Key resource
Download a PDF booklet on this topic.
More resources
A/Prof Peter Grimison, Medical Oncologist, Chris O’Brien Lifehouse and Royal Prince Alfred Hospital, NSW; Marc Diocera, Genitourinary Nurse Consultant, Peter MacCallum Cancer Centre, VIC; A/Prof Peter Heathcote, Urologist, Brisbane Urology Clinic, QLD; Dr Michael Huo, Radiation Oncologist, Princess Alexandra Hospital, QLD; A/Prof Joseph McKendrick, Medical Oncologist, Epworth Eastern Hospital, VIC; Dr Tonia Mezzini, Sexual Health Physician, East Obstetrics and Gynaecology, SA; Dominic Oen, Clinical Psychologist, Bankstown Cancer Centre, NSW; Dr Benjamin Thomas, Urological Surgeon, The Royal Melbourne Hospital and The University of Melbourne, VIC; Paul Zawa, Consumer.
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