Testicular cancer

What is it?

Testicular cancer is an abnormal, uncontrolled growth of cells that form a tumour in one or both testes. Men have two testicles (testes, gonads) that are located in the scrotum, a pouch of loose skin found below and at the base of the penis. The testicles are responsible for producing sperm and male hormones (mainly testosterone) that regulate reproductive organ development.

Testicular cancer is the most common cancer in males between 15 and 34 years of age. About 700 men are diagnosed with testicular cancer in Australia each year. Caucasian males are at a greater risk than are those of African, Hispanic, or Asian descent, although the cause for this additional risk is not known. Other risk factors include undescended testicles (cryptorchidism), abnormal development of the testes (gonadal dysgenesis), a sex chromosome disorder, Klinefelter’s syndrome, and a family or personal history of testicular cancer.

Germ cell tumours account for about 90% of testicular cancers. They are separated into seminomas and non-seminomas. Seminomas make up about half of testicular germ cell tumours, occurring most frequently in middle-aged men. They tend to grow very slowly and usually do not metastasise. Non-seminomas occur earlier in life. They mainly affect men in their 20’s and tend to be more aggressive.

About 4-5% of all (and 20% of children’s) testicular cancers form in the stromal tissues that support the testes and produce hormones. These tumours may secrete oestradiol, a form of the female hormone oestrogen, resulting in breast tissue development (gynaecomastia).

While testicular cancer is one of the most curable forms of cancer, with a cure rate in excess of 90%, most types will spread if left unchecked, first invading and damaging the other testicle before metastasising and being carried by the lymph nodes to other body organs, such as the lungs. Early detection and treatment is crucial to a favourable outcome.