Testicular cancer occurs in the cells of one or both testicles. The testicles are part of the male reproductive system. Sometimes called testes, they are oval-shaped glands found inside the scrotum (a sac of skin that hangs directly behind the penis). The testicles make male hormones and produce sperm.
Because there are different types of cells in the testicles, there are different types of testicular cancer, and they are treated differently. The cells that make sperm are called germ cells. Most testicular cancers begin as one of two types of germ-cell tumors: seminoma or nonseminoma. A third type of testicular tumor is called a stromal tumor. In addition to the tumors that begin in the testicle, there are secondary tumors that spread to the testicles from cancer in other parts of the body.
- Seminomas typically occur in men in their late 30s to early 50s but can occur at any age. In general these tumors respond well to radiation therapy and chemotherapy.
- Nonseminomas are usually found in younger men from the late teens to early 40s. These tumors are generally more aggressive than seminomas and spread rapidly. Chemotherapy is often very effective in treating nonseminomas.
- Stromal tumors grow in the cells that make hormones and in the supportive tissues of the testicles. Most of the time, these tumors are not cancerous and do not spread beyond the testicle. They can be removed by surgery. However, if a stromal tumor is cancerous and metastasizes to other parts of the body, aggressive treatment is required. These tumors do not respond well to radiation or to chemotherapy.
- Secondary tumors are the most common form of testicular cancer for men over the age of 50. Lymphoma is the most common source of these secondary tumors, but metastases from cancers in other organs may spread to the testicles. Treatment for a secondary testicular tumor is specific to the type of cancer and often requires surgery, radiation therapy, and chemotherapy.
Most often (90% of the time) testicular cancer presents as a lump in the testicle. You should see your doctor if you have any of the following symptoms.
- a painless lump or swelling in the testicle
- pain or discomfort in the testicle or scrotum
- a dull ache in the lower abdomen or groin
- a sudden build-up of fluid in the scrotum
- a feeling of heaviness in the scrotum
- enlarged or tender breasts
- loss of sex drive
Sometimes a man finds a lump in his testicle during self-examination or his doctor finds something suspicious during a physical. Oftentimes there are no symptoms.
The exact cause of testicular cancer is unknown. Research is ongoing into the causes and risk factors for testicular cancer. The following is a list of potential risk factors; however, many men who have testicular cancer do not have any of the risk factors.
- Cryptorchidism (undescended testicle). This problem occurs in development of the fetus when one or both testicles, which develop in the belly, do not move down into the scrotum. It is the main risk factor for testicular cancer.
- Abnormal development of the testicles. Men born with abnormalities of the testicles, penis or kidneys, or those with an inguinal hernia may be at greater risk.
- Klinefelter’s syndrome. Men born with this condition have an extra X chromosome, which results in low levels of male hormones, infertility, breast enlargement, and small testicles. They may have an increased risk of testicular cancer.
- History of testicular cancer. Having had cancer in one testicle increases the risk of developing it on the other side.
- Family history of testicular cancer. If a man has testicular cancer, his brothers or sons may be at higher risk to develop it.
- Age between 15 and 34. While testicular cancer can occur at any age, it is most often a disease of young men.
- Race. White men are more likely to develop testicular cancer than black, Asian, or Hispanic men. The reason for this is not known.
- Human immunodeficiency virus (HIV). Men infected with HIV may have a slightly increased risk of testicular cancer.