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Types of Cancer > Testicular Cancer > Overview
Testicular Cancer: The Basics
Carolyn Vachani, MSN, RN, AOCN
Affiliation:
OncoLink
Last Modified: March 7, 2008
What is a testicle?
Testicles (also called testes or gonads) are male sex glands found behind the penis in a sac of skin called the scrotum. These glands are responsible for producing and storing sperm, as well as producing male hormones.
What is testicular cancer?
Testicular cancer begins when cells within the testicle become cancerous and begin to grow out of control. Ninety-five percent of testicular tumors are a type called germ cell tumors. Other types of tumors found in the testicle are uncommon, and so this article will only address germ cell tumors.
Testicular cancer is classified as one of two types: seminoma, which accounts for 40% of all testicular cancers, and nonseminoma, which includes four sub-types. Seminomas include classic or anaplastic seminoma, which account for 35% of testicular cancers and generally occur between the ages of 25 and 45 years. Spermatocytic seminoma accounts for only 5% of testicular tumors and occurs later in life, with an average age at diagnosis of 65 years.
The nonseminomas include: choriocarcinoma (<1%), embryonal carcinoma (24%), teratoma (30%), and yolk sac tumors (<1%). The peak occurrence for nonseminomas is between ages 20 and 30. Most testicular tumors contain a mixture of both cell types and are called mixed germ-cell tumors. If a tumor contains any proportion of non-seminomatous tissue, it is classified as a nonseminoma. If the tumor contains only seminoma cells, it is called a pure seminoma. The two types behave differently and have different prognoses and treatments, so distinguishing between seminoma and nonseminoma is critical to appropriate treatment.
The American Cancer Society estimates that 8.090 new cases of testicular cancer will be diagnosed in 2008, accounting for only 1% of cancers in men. However, it is the most common form of cancer in men ages 15 to 35 years. In addition, the disease is five times more common in whites than in blacks or Asians.
Am I at risk for testicular cancer?
The cause of testicular cancer is still unknown, but a few things have been linked to a higher risk of developing the disease. An undescended testicle (also called cryptorchidism) is a condition where the testicle did not move into the scrotum before birth. Surgery can be performed to correct the problem and this may lower the risk of developing testicular cancer, particularly when performed before 6 years of age, although this has not been definitely proven. While the risk is higher with this history, it is important to remember that only 1-5% of boys born with an undescended testicle will go on to develop testicular cancer, and 90% of cases are in men without this history.
Men whose testicles did not develop normally are also at higher risk. Klinefelter's Syndrome is a disorder characterized by low levels of male hormones, sterility, breast enlargement, and small testes. This syndrome carries an increased risk of testicular cancer. Men who have already had testicular cancer have a two to five percent chance of developing cancer in the opposite testicle during the 25 years following diagnosis.
Other risk factors are not clearly understood. Rates have been steadily increasing over the past 40 years, and some experts attribute this to environmental factors and estrogen exposure, either in utero or after birth. Men with a first degree relative (father, brother, son) with the disease are at an increased risk of developing the disease. Researchers have looked for a specific genetic abnormality that could be tested for in families that are affected (like the BRCA 1&2 breast cancer genes), but have not found one.