The testicles (also called testes or gonads) are located under the penis in a sac-like pouch called the scrotum. They produce male hormones (androgens) such as testosterone, and they make sperm, the male cells needed to fertilize a female egg cell to start a pregnancy. Most types of testicular cancer develop in the sperm-producing cells known as germ cells. Testicular cancer is almost always curable if found early, and it is usually curable even when found at a later stage.
Forms of testicular cancer
Germ cell tumors account for more than 90 percent of testicular cancers and fall into two main types: seminomas and non-seminomas. Seminomas tend to grow and spread more slowly than non-seminomas.
Classical (or typical) seminomas account for more than 95 percent of seminomas and usually occur in men between 25 and 45.
Spermatocytic seminomas are rare and tend to occur in older men.
Non-seminoma tumors fall into four main types: embryonal carcinoma, yolk sac carcinoma (this is the most common form of testicular cancer in children), choriocarcinoma (a very rare and fast-growing type of testicular cancer in adults), and teratoma. Most non-seminomas are a mix of at least two different subtypes of germ cell tumor. Even if a tumor is 99 percent seminoma and 1 percent non-seminoma, it is diagnosed and treated as a non-seminoma.
Stromal tumors start in the supportive and hormone-producing tissues, or stroma, of the testicles. These tumors account for less than 5 percent of adult testicular tumors, but up to 20 percent of childhood testicular tumors. The main types are Leydig cell tumors and Sertoli cell tumors. These tumors are usually benign and seldom spread. However, those that become cancerous and spread usually do not respond well to chemo or radiation therapy.
Other, less common types of testicular tumors include carcinoma of the rete testis, which is a part of the testicles, and testicular lymphoma.
Risk factors for testicular cancer
Age — About half of testicular cancers occur in men between the ages of 20 and 34. However, this cancer can affect males of any age, including infants and elderly men.
Cryptorchidism — (undescended testicle) Men with this condition, in which one or both testicles have not moved down into the scrotum before birth, have an increased risk of developing testicular cancer. This risk may be lowered if surgery is used to fix the condition before puberty. Because cryptorchidism is often fixed at a young age, many men may not know if they had the condition.
Family history and genetics — Having a father or especially a brother who has had testicular cancer increases the risk of developing the disease. However, few testicular cancers occur in families and most men with testicular cancer do not have a family history of the disease. Kleinfelter’s syndrome is an inherited disease that is also linked to an increased risk of testicular cancer.
Personal history — Men who have had cancer in one testicle have an increased risk of developing cancer in the other testicle. About 2 to 4 percent of men cured of cancer in one testicle will at some point develop cancer in the other testicle.
Race and ethnicity — The risk of testicular cancer among white men is about 4 to 5 times that of black and Asian American men. Although testicular cancer is rare in black men, they are more likely to die of the disease than white men. This is true particularly if the cancer has spread to the lymph nodes or other parts of the body when it is diagnosed. The risk for Native Americans falls between that of Asians and whites.
Human immunodeficiency virus (HIV) — Men with HIV or acquired immune deficiency syndrome (AIDS) caused by HIV have a slightly higher risk of developing seminoma.
Symptoms of testicular cancer
A painless lump or swelling on either testicle
Pain, discomfort, or numbness in a testicle or the scrotum, with or without swelling
Change in the way a testicle feels or a feeling of heaviness in the scrotum
Change in testicle size
Dull ache in the lower abdomen or groin
Sudden buildup of fluid in the scrotum
Breast tenderness or growth. Although rare, some testicular tumors make hormones that cause breast tenderness or growth of breast tissue, a condition called gynecomastia.
Swelling of one or both legs or shortness of breath from a blood clot
Early puberty in boys
Many symptoms and signs of testicular cancer are similar to those caused by noncancerous conditions.
Symptoms of advanced testicular cancer
Low back pain from cancer spread to the lymph nodes in back of the belly
Shortness of breath, chest pain, or a cough (even coughing up blood) from cancer spread to the lungs
Belly pain, either from enlarged lymph nodes or because cancer has spread to the liver
Headaches or confusion from cancer spread to the brain
How is testicular cancer treated with radiation?
External-beam radiation therapy (EBRT) is the type of radiation therapy used for testicular cancer, specifically for stage I, IIA, and IIB pure seminoma. Radiation for stage I seminoma is now used less often than in the past. Instead, surveillance or, less commonly, chemotherapy is used.
Radiation may be used after orchiectomy (the operation to remove the testicle) and is directed at the lymph nodes at the back of the abdomen, to kill cancer cells that surgery might have missed.
Radiation may be used to treat testicular cancer (both seminoma and non-seminoma) that has spread to distant organs (like the brain).
More extensive information about testicular and other cancers may be found at these sites:
American Cancer Society: Cancer.org
American Society of Clinical Oncology: Cancer.net
National Cancer Institute: Cancer.gov