Definition
Testicular cancer, also known as cancer of the testes, occurs when germ cells (the cells that become sperm) experience abnormal growth. Germ cells, like stem cells, have the potential to form any cell in the body. Normally this ability is dormant until the sperm fertilizes an egg. When germ cells become cancerous, they multiply unchecked, forming a mass of cells called a tumor, and invade normal tissue.
Testicular cancer can metastasize, meaning that it can spread to other parts of the body. During metastasis cells leave the original tumor and migrate to other parts of the body through blood and lymph vessels, forming a new tumor. Testicular cancer metastasis most often involves the abdomen, lungs and brain. Testicular cancer can spread rapidly and is deadly if left untreated.
Description
The testicles make up one portion of the male reproductive system. Normally, they are each somewhat smaller than a golf ball in size and are contained within the scrotum. The testicles are a man's primary source of male hormones, particularly testosterone. They also produce sperm.
There are several types of cells contained in the testicles, and any of these may develop into one or more types of cancer. Over 90% of all testicular cancers begin in cells called germ cells. There are two main types of germ cell tumors in men: seminomas and nonseminomas. Seminomas make up about 40% of all testicular germ cell tumors. Nonseminomas make up a group of cancers, which include choriocarcinoma, yolk sac tumors, embryonal carcinoma, and teratoma.
Although testicular cancer accounts for less then 2% of all cancers in men, it is the most commonly seen cancer in young men aged 15 to 35. It is also one of the most curable.
The American Cancer Society estimates that approximately 8,980 new cases of testicular cancer will be diagnosed in American men in 2004. In addition, about 360 men will die of the disease during that year. Although the incidence of testicular cancer is rising, having doubled since 1975, it is still rare. Scandinavian countries have the highest rate in the world. Germany and New Zealand also have high rates. The lowest incidences of testicular cancer are in Asia and Africa.