Testicular cancer is the most common form of cancer among males age 15 to 44. After motor vehicle accidents and suicide, cancer is the leading cause of death in this age group, followed by homicide, heart disease, and HIV. Testicular cancer is known as the young man's cancer. Early detection is the key to survival. Testicular cancer has a very fast onset since the tumors can be very aggressive. When the cancer is confined to the testicles, there is often no pain. By the time pain develops, it is often a sign that the cancer has already spread. Survival rates increase significantly if treatment has begun before the cancer has a chance to metastasize. Upon reaching puberty, all men should conduct testicular self-exams at least monthly and preferably every time they shower. The purpose of a testicular self-exam is to familiarize yourself with the size, shape and texture of your testicles. If you notice any change, especially a lump, it is imperative that you see your doctor immediately. Diagnosis is non-invasive, and involves using ultrasound to look at the density, size and shape of the testicles and other masses in the scrotum.