- 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.
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The testicles are two oval glands that sit behind the penis in a pouch of skin called the scrotum. They are part of the male reproductive system and are also called testes (or a testis, if referring to one).
Role of the testicles
The testicles produce and store sperm. They also produce the sex hormone testosterone, which is responsible for the development of male characteristics, such as facial hair, a deeper voice and increased muscle mass, as well as sexual drive (libido).
Epididymis, spermatic cord and vas deferens
A tightly coiled tube at the back of each testicle called the epididymis stores immature sperm. The epididymis connects the testicle to the spermatic cord. The spermatic cord runs through the groin region into the pelvis and contains blood vessels, nerves, lymph vessels and a tube called the vas deferens. The vas deferens carries sperm from the epididymis to the prostate gland.
Seminal vesicles and prostate gland
Two small glands called seminal vesicles sit above the prostate gland. The seminal vesicles and prostate gland produce fluids that make up a large part of semen. Semen also contains sperm from the testicles and is ejaculated from the penis during sexual climax.
Lymph nodes and vessels
There are many lymph nodes (also called lymph glands) and lymph vessels around the testicles and in the abdomen. These are part of the lymphatic system and are important for resisting and fighting disease (immunity). The nodes and vessels also drain lymphatic fluid (lymph) from the tissues back into the bloodstream.
The male reproductive system
Who gets testicular cancer?
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.
What causes testicular cancer?
The causes of testicular cancer are unknown, but certain factors may increase your risk of developing it.
If you who have previously had cancer in one testicle, you are more likely to develop cancer in the other testicle. ITGCN is also a risk factor.
Before birth, testicles develop inside the abdomen. By birth, or within the first six months of life, the testicles should move down into the scrotum.
If the testicles don’t descend by themselves, doctors perform an operation to bring them down. Although this reduces the risk of developing testicular cancer, people born with undescended testicles are still more likely to develop testicular cancer than men born with descended testicles.
Sometimes gene mutations are passed on in families. If your father or brother has had testicular cancer, you are slightly more at risk of cancer. But family history is only a factor in a small number (about 2%) of people who are diagnosed with testicular cancer. If you are concerned about your family history of testicular cancer, you can ask your doctor for a referral to a specialist called a urologist.
Having difficulty conceiving a baby (infertility) can be associated with testicular cancer. Testicular cancer can cause changes in your testosterone levels as well as genetic damage to sperm cells. As a result, infertility is considered a risk factor for testicular cancer.
HIV and AIDS
There is some evidence that people with HIV (human immunodeficiency virus) and AIDS (acquired immune deficiency syndrome) have an increased risk of testicular cancer.
Some congenital defects
Some people are born with an abnormality of the penis called hypospadias. This causes the urethra to open on the underside of the penis, rather than at the end. People with this condition are at an increased risk of developing testicular cancer. Likewise, there may also be an increased risk for people born with a lump in the groin known as an inguinal hernia, even when it has been repaired.
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.
What types are there?
The most common testicular cancers are called germ cell tumours. There are two main types, seminoma and non-seminoma.
Germ cell tumours
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.
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Prof Declan Murphy, Urologist and Director of Genitourinary Oncology, Peter MacCallum Cancer Centre, VIC; Gregory Bock, Urology Cancer Nurse Coordinator, WA Cancer and Palliative Care Network, North Metropolitan Health Service, WA; A/Prof Nicholas Brook, Senior Consultant Urological Surgeon, Royal Adelaide Hospital and The University of Adelaide, SA; Clinical A/Prof Peter Grimison, Medical Oncologist, Chris O’Brien Lifehouse and The University of Sydney, NSW; Dr Tanya Holt, Senior Radiation Oncologist, Radiation Oncology Princess Alexandra Hospital Raymond Terrace (ROPART), QLD; Brodie Kitson, Consumer; Elizabeth Medhurst, Genitourinary and Stereotactic Ablative Body Radiotherapy (SABR) Nurse Consultant, Peter MacCallum Cancer Centre, VIC; Rosemary Watson, 13 11 20 Consultant, Cancer Council Victoria.
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