What Causes Testicular Cancer?

The precise causes of testicular cancer are not known. The first signs of testicular cancer are usually pain and swelling of one or both testicles, but some cases do not cause any symptoms in the early stages.

Risk Factors

Although the exact causes of testicular cancer are not known, possible risk factors include the following:

• Age - Testicular cancer is the most common form of cancer in young men between the ages of 20 and 54. However, testicular cancer can affect men of all ages, including infants.

• Personal or family history of testicular cancer - Men who have had testicular cancer in the past are more likely to develop the cancer again, particularly in the other testicle. Also at increased risk are men with a first-degree relative (father, brother, or son) who has had testicular cancer. Researchers have not identified a specific genetic abnormality, such as the BRCA I and II genes in breast cancer, for testicular cancer.

• Race and ethnicity - The rate of testicular cancer is higher in Caucasian men than in other populations.

• Undescended testicle (cryptorchidism) - This is the main risk factor for this cancer. During normal development of a male fetus (unborn baby), the testicles are formed inside the body. During fetal development, the testes descend into the scrotum so that they are located outside of the body at birth. Sometimes, one testicle (or, more rarely, both testicles) does not move into the proper position before birth. In these cases, the child is born with an undescended testicle, a condition known as cryptorchidism. This condition can be corrected with surgery, and most children go on to become normal adult males. However, males who were born with an undescended testicle appear to be at greater risk of developing testicular cancer. In these men, there is an equal chance of testicular cancer developing in either testicle, even if only one organ was originally affected.

• Klinefelter’s syndrome - Men with this disorder have an abnormality of the sex chromosomes that causes low levels of male sex hormones. They are at increased risk for germ cell tumors.

• Human Immunodeficiency virus (HIV) infection - Men with this infection have a slightly higher risk for testicular cancer.

• Birth defects - Abnormalities of the penis, scrotum, testes, or kidneys (which develop along with the genitalia in male fetuses) that are present at birth appear to increase a male’s risk of developing testicular cancer. The risk is also increased in males who were born with an inguinal hernia—a condition in which part of an internal organ (usually the intestines) protrude through a weak area or tear in the groin (area where the lower abdomen meets the thigh).