Sometimes, however, cells get out of control. They divide too much and form masses known as tumors. Some tumors may interfere with body functions and require surgical removal, but they do not spread to other parts of the body. These are known as benign tumors. There they may form more malignant tumors.
Cancers can spread rapidly or take years.
Cancer of the testes can spread rapidly and be deadly. With modern treatment, it is one of the most curable forms of cancer. Types of Testicular Cancer Almost all testicular tumors occur in the cells that produce sperm and are known as germ cells. This is the most common type of testicular cancer, accounting for 30 to 40 percent of all such tumors. It occurs most often in men between the ages of 25 and 45 and is usually slow growing.