What is testicular cancer?

The vast majority of testicular cancer (95%) develop from the germinal cells of the testes. These germ cell tumours are divided into two sub-groups: seminomas and non-seminomas.

Less than 5% of testicular tumours are the non-germ cell tumours and include rarities such as Leydig cell tumours, Sertoli cell tumours and gonadoblastomas and will not be discussed further. In this article the term testicular cancer will refer to germ cell testicular tumours.

The incidence of testicular cancer shows marked variation among different countries, races and socio-economic groups. The disease is most common in Scandinavia and rare in Africa.

The cause of testicular cancer is unknown. Carcinoma in situ (CIS) is believed to be the precursor of seminoma and non-seminoma. Men with undescended testicles have a 5–10 times increased risk of developing testicular cancer, compared to the general population. Five percent of patients who have had a testicular cancer develop a second cancer on the other side.

Testicular cancer typically presents with a painless lump in the testis. Left untreated, the tumour cells can spread via the lymphatic pathways to the retroperitoneal glands around the aorta at the level of the kidneys. Later spread via the blood stream to the lungs, liver, bone and brain can occur. Most patients have disease confined to the testis or the regional lymph glands at presentation.

Many testicular cancers produce tumour markers. These are proteins overproduced by the tumour cells and can be measured in the blood. They can be useful in the diagnosis, staging and monitoring of treatment.

Testicular cancer is one of the most treatable cancers. The vast majority of patients, including those with widespread metastatic disease, are cured by modern day chemotherapy and/or radiotherapy. The treatment regimes, however, are not without complications and despite the excellent overall results, a small group of poor prognosis patients do badly despite intensive therapy.