Testicular cancer

Testicular cancer is not a common cancer, but it is the most commonly diagnosed cancer after skin cancer in 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.

The causes of testicular cancer are unknown, but certain factors may increase a man’s risk of developing it:

Personal history

Men who have previously had cancer in one testicle are more likely to develop cancer in the other testicle. ITGCN is also a risk factor.

Undescended testicles

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, men born with undescended testicles are still more likely to develop testicular cancer than men born with descended testicles.

Family history

Sometimes gene mutations are passed on in families. A man with a father or brother who has had testicular cancer is slightly more at risk of cancer. However, family history is only a factor in a small number (about 2%) of men 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 urologist. The urologist can provide advice on self-examination for you and your family members.

Infertility

Having difficulty conceiving a baby (infertility) is associated with ITGCN, undescended testicles and, occasionally, genetic abnormalities. Because these are risk factors for testicular cancer as well, infertility is also considered a risk factor for testicular cancer.

HIV and AIDS

There is some evidence that men with HIV (human immunodeficiency virus) and AIDS (acquired immune deficiency syndrome) have an increased risk of testicular cancer, although the reasons are unknown.

Some congenital defects

Some men 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. Men with this condition are at increased risk of testicular cancer in the future. Likewise, there may be an increased risk for men born with a lump in the groin known uinal hernia, even when it has been repaired.

The most common testicular cancers are called germ cell tumours. There are two main types, which look different under a microscope.

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.

Other types of cancer, such as lymphoma, can also involve the testicles. For information about lymphoma, call Cancer Council 13 11 20 or see Hodgkin lymphoma and non-Hodgkin lymphoma.

Intratubular germ cell neoplasia (ITGCN)

Some germ cell 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.

Click on the icon below to download a PDF booklet on testicular cancer.