Testicular Cancer
Testicular cancer forms in tissues of the testis (one of two egg-shaped glands inside the scrotum that make sperm and male hormones). Testicular cancer usually occurs in young or middle-aged men. The testicles (also called testes or gonads) are a pair of male sex glands. They produce and store sperm and are the main source of testosterone (male hormones) in men. These hormones control the development of the reproductive organs and other male physical characteristics. The testicles are located under the penis in a sac-like pouch called the scrotum.
Based on the characteristics of the cells in the tumor, testicular cancers are classified as seminomas or nonseminomas. Other types of cancer that arise in the testicles are rare and are not described here. Seminomas may be one of three types: classic, anaplastic, or spermatocytic. Types of nonseminomas include choriocarcinoma, embryonal carcinoma, teratoma, and yolk sac tumors. Testicular tumors may contain both seminoma and nonseminoma cells.
Testicular cancer accounts for only 1 percent of all cancers in men in the United States. About 8,000 men are diagnosed with testicular cancer, and about 390 men die of this disease each year. Testicular cancer occurs most often in men between the ages of 20 and 39, and is the most common form of cancer in men between the ages of 15 and 34. It is most common in white men, especially those of Scandinavian descent. The testicular cancer rate has more than doubled among white men in the past 40 years, but has only recently begun to increase among black men. The reason for the racial differences in incidence is not known. 
Who is at Risk for Devleloping Testicular Cancer?
The exact causes of testicular cancer are not known. However, studies have shown that several factors increase a man's chance of developing this disease. The following are known risk factors:
Undescended testicle (cryptorchidism): Normally, the testicles descend from inside the abdomen into the scrotum before birth. The risk of testicular cancer is increased in males with a testicle that does not move down into the scrotum. This risk does not change even after surgery to move the testicle into the scrotum. The increased risk applies to both testicles.
Congenital abnormalities: Men born with abnormalities of the testicles, penis, or kidneys, as well as those with inguinal hernia (hernia in the groin area, where the thigh meets the abdomen), may be at increased risk.
History of testicular cancer: Men who have had testicular cancer are at increased risk of developing cancer in the other testicle.
Family history of testicular cancer: The risk for testicular cancer is greater in men whose brother or father has had the disease.
Treatment for Testicular Cancer
Although the incidence of testicular cancer has risen in recent years, more than 95 percent of cases can be cured. Treatment is more likely to be successful when testicular cancer is found early. In addition, treatment can often be less aggressive and may cause fewer side effects.
Most men with testicular cancer can be cured with surgery, radiation therapy, and/or chemotherapy. The side effects depend on the type of treatment and may be different for each person.
Seminomas and nonseminomas grow and spread differently and are treated differently. Nonseminomas tend to grow and spread more quickly; seminomas are more sensitive to radiation. If the tumor contains both seminoma and nonseminoma cells, it is treated as a nonseminoma. Treatment also depends on the stage of the cancer, the patient's age and general health, and other factors. Treatment is often provided by a team of specialists, which may include a surgeon, a medical oncologist, and a radiation oncologist.