Most testicular cancers develop in men younger than age 40. It is one of the most common cancers in young men, developing in about 8,000 men each year and causing about 400 deaths. Among the types of cancer that commonly develop in the testes are seminoma, teratoma, embryonal carcinoma, and choriocarcinoma.
The cause of testicular cancer is not known, but men whose testes did not descend into the scrotum (cryptorchidism—see Undescended Testes and Retractile Testes) by age 3 have a greater chance of developing testicular cancer than do men whose testes descended by that age. Cryptorchidism is best corrected surgically in childhood. Correcting cryptorchidism decreases the risk of testicular cancer. However, even if cryptorchidism is corrected, the risk of cancer is still higher than for men who never had cryptorchidism. Cancer can also occur in the other testis even if it descended normally. Sometimes in adults, doctors recommend removal of a single undescended testis to reduce the risk of cancer.
Testicular cancer may cause an enlarged testis or a lump. A testis normally feels like a smooth oval, with the epididymis attached behind and on top. Testicular cancer causes a firm, growing lump in or attached to the testis. With cancer, the testis loses its normal shape, becoming large, irregular, or bumpy. Although testicular cancer is usually painless, the testis or lump may hurt when lightly touched and may even hurt without being touched. A firm lump on the testis requires prompt medical attention. Occasionally, blood vessels rupture within the tumor, yielding a suddenly enlarged, severely painful swelling.
Physical examination and ultrasonography may indicate whether a lump is part of the testis and whether it is solid (and thus more likely to be cancer) or filled with fluid (cystic). Determining the blood levels of two proteins, alpha-fetoprotein and human chorionic gonadotropin, may help in making the diagnosis. The levels of these proteins often increase in men with testicular cancer. Additional testing, including a chest x-ray and computed tomography, may be done to determine whether the cancer has spread. Most doctors recommend that young men check their own testes for lumps about once per month.
The initial treatment for testicular cancer is surgical removal of the entire affected testis (radical orchiectomy). An artificial testis (prosthesis) can be placed if the man desires. The other testis is not removed, so men retain adequate levels of male hormones and can remain fertile. Infertility sometimes occurs in men with testicular cancer, but fertility may return after treatment. Sperm banking may be possible before treatment.
With cancers other than seminomas, lymph nodes in the abdomen are also removed (retroperitoneal lymph node dissection) because the cancer often spreads there first. Radiation therapy may be curative for a seminoma.
A combination of surgery and chemotherapy often cures testicular cancer that has spread. Blood levels of alpha-fetoprotein and human chorionic gonadotropin that were elevated at diagnosis decline after successful treatment. If levels rise after treatment, the cancer may have recurred.
The prognosis for men with testicular cancer depends on the type and extent of the cancer but is usually excellent if the cancer has not spread. Even if the cancer has spread, cure is sometimes possible.