Testicular cancer is rare in the population but is the most common cancer in young men, between the ages of 15 and 34 years. Most cases of testicular cancer arise from sperm-producing cells. Testicular cancer can be quite dangerous, especially since it usually does not cause pain. Symptoms include a lump in the testicle, swelling or a change in consistency of the testicle, perhaps accompanied by a dull ache in the lower abdomen, groin, or scrotum. It is not yet clear what causes testicular cancer. One major known risk factor, however, is cryptorchidism, a condition in which the testes fail to descend into the scrotum and are retained within the abdomen. Testicular cancer is one of the most curable of all cancers.
In the USA, the incidence of testicular cancer has increased about 50% during the 20 years up to 1994. Worldwide it has tripled since the 1940s. The risk of developing a malignant tumour is about five times greater in men with undescended testes than in those with normal testes.
In 1997 in Denmark, there was 300 per cent more testicular cancer than in 1947.
One of the causes of testicular cancer is a man's exposure to harmful chemicals in his mother's bloodstream while still a foetus.