DEAR MAYO CLINIC: Are there ever early signs of testicular cancer? If so, what are they? What treatments are available?ANSWER: Yes, there are early signs of testicular cancer that are often noticeable, particularly when males do regular testicular self-exams. Identifying testicular cancer in its early stages is important because, as with many kinds of cancer, the sooner it is detected, the better the chance for successful treatment.Testicular cancer occurs in the testicles, which are located inside the scrotum, a loose bag of skin underneath the penis. The testicles produce male sex hormones and sperm for reproduction. When compared with other types of cancer, testicular cancer is rare. But in the United States, testicular cancer is the most common cancer in males between the ages of 15 and 34.The most common early sign of testicular cancer is a firm lump within or enlargement of a testicle. These nodules or masses are usually painless. To catch testicular cancer in its earliest stages, I recommend that my patients get in the habit of performing testicular self-exams once a month. A good time to do this is during or after a shower because the heat from the water relaxes the scrotum, making it easier to find anything unusual.The testicles are usually smooth, oval and somewhat firm. It is normal for one testicle to be slightly larger than the other. Also, the cord leading upward from the top of the testicle is a normal structure within the scrotum. If you notice any new lumps or bumps, or any other changes during a self-exam, make an appointment to have them evaluated by your doctor. Blood tests, imaging exams such as ultrasound and other diagnostic tests can help your doctor determine if a lump may be testicular cancer.Fortunately, even when cancer has spread, testicular cancer often responds well to treatment and, in most cases, a cure is possible. But if you notice any changes in a testicle, particularly new lumps or enlargement, make an appointment to see your doctor as soon as possible.– R. Houston Thompson, M.D., Urology, Mayo Clinic, Rochester, Minn.