Seminoma Health Channel

Definition

Testicular cancer is an abnormal, rapid, and invasive growth of cancerous (malignant) cells in the testicles (male sex glands adjacent to the penis).

Alternative Names

Cancer - testes; Germ cell tumor; Seminoma

Causes, incidence, and risk factors

Although the exact cause of testicular cancer is unknown, several factors seem to increase risk. These include a past medical history of undescended testicle(s), abnormal testicular development, Klinefelter's syndrome (a sex chromosome disorder that may be characterized by low levels of male hormones, sterility, development of breasts, and small testes), or previous testicular cancer.

Other factors are under investigation as possible causes. They include exposure to certain chemicals and infection with the human immunodeficiency virus (HIV). A family history of testicular cancer may increase risk. There is no link between vasectomy (an operation to cause sterility) and elevated risk of testicular cancer.

Between 6,000 and 8,000 men will be diagnosed with testicular cancers each year. Although testicular cancer accounts for 1% of all cancers in men, it is the most common form of cancer in young men 15 to 40 years old. It may also occur in young boys, but only about 3% of all testicular cancer is found in this group.

White American men have about five times the risk of African-American men and more than twice the risk of Asian-American men. The risk for testicular cancer has doubled among white Americans in the past 40 years but has remained the same for African-Americans. The reasons for these differences are not known.

Testicular cancers may be classified as follows:

• Seminomas account for about 30-40% of all testicular tumors. These are usually is found in men in their 30s and 40s.