Testicular cancer is cancer that starts in the testicles, the male sex glands located next to the penis.

The exact cause of testicular cancer is unknown. However, several factors seem to increase a man's risk for the condition. They include:

• Abnormal testicle development
• History of undescended testicle(s)
• History of testicular cancer
• Klinefelter syndrome

Other factors under investigation as possible causes include exposure to certain chemicals and HIV infection. A family history of testicular cancer may also increase risk.

There is no link between vasectomy and testicular cancer.

Testicular cancer accounts for only 1% of all cancers in men in the U.S., but is the most common form of cancer in men age 15 - 40. In rare cases, it may occur at a younger age.

White men are five times more likely to develop this type of cancer than African Americans. White men are twice as likely as Asian-American men to have testicular cancer.

There are two main types of testicular cancer: Seminomas and nonseminomas. These cancers grow from germ cells, the cells that make sperm.

Seminoma: This is a slow-growing form of testicular cancer usually found in men in their 30s and 40s. The cancer is usually just in the testes. However, it can spread to the lymph nodes.

Nonseminoma: This more common type of testicular cancer tends to grow more quickly than seminomas. Nonseminoma tumors are often made up of different cell types, and are identified according to the cells in which they start to grow. Nonseminoma testicular cancers include:

• Choriocarcinoma (rare)
• Embryonal carcinoma
• Teratoma
• Yolk sac tumor

A stromal tumor is a rare type of testicular tumor. Such tumors are usually not cancerous. The two main types of stromal tumors are Leydig cell tumors and Sertoli cell tumors. Leydig cells release the hormone testosterone, and Sertoli cells are where sperm matures. Stromal tumors may be seen during childhood.

• Discomfort, pain, in the testicle or a feeling of heaviness in the scrotum
• Dull ache in the back or lower abdomen
• Enlargement of a testicle or a change in the way it feels
• Excess development of breast tissue (gynecomastia), but this can also occur normally in adolescent males who do not have testicular cancer
• Lump or swelling in either testicle
• Symptoms in other parts of the body, such as the lungs, abdomen, pelvis, or brain (if the cancer has spread)

Note: There may be no symptoms.

A physical examination typically reveals a firm lump (mass). When the health care provider holds a flashlight up to the scrotum, the light does not pass through the mass.

Other tests include:

• Abdominal CT scan
• Blood tests for tumor markers: alpha fetoprotein (AFP), human chorionic gonadotrophin (beta HCG), and lactic dehydrogenase (LDH)
• Chest x-ray
• Ultrasound of the scrotum

Tissue biopsy is usually done by removing the testicle with surgery and then examining the tissue.

Treatment depends on the:

• Type of tumor
• Stage of the tumor
• Extent of the disease

Most patients can be cured.

Once cancer is found, the first step is to determine the type of cancer cell by examining it under a microscope. The cells can be seminoma or nonseminoma. If both seminoma and nonseminoma cells are found in a single tumor, the tumor is treated as a nonseminoma.

The next step is to determine how far the cancer has spread to other parts of the body. This is called "staging."

• Stage I cancer has not spread beyond the testicle.
• Stage II cancer has spread to lymph nodes in the abdomen.
• Stage III cancer has spread beyond the lymph nodes (it could be as far as the liver or lungs).

Three types of treatment can be used.

1. Surgical treatment removes the testicle (orchiectomy) and associated lymph nodes (lymphadenectomy). This is usually performed in the case of both seminoma and nonseminomas.
2. Radiation therapy using high-dose x-rays or other high-energy rays may be used after surgery to prevent the tumor from returning. Radiation therapy is usually only used for treating seminomas.
3. Chemotherapy uses drugs such as cisplatin, bleomycin, and etoposide to kill cancer cells. This treatment has greatly improved survival for patients with both seminomas and nonseminomas.

Joining a support group where members share common experiences and problems can often help the stress of illness. Your local branch of the American Cancer Society may have a support group.

Lance Armstrong, a famous cyclist, is a survivor of testicular cancer. His web site -- www.laf.org -- offers support and information for patients with testicular cancer.

The National Cancer Institute also offers such information. Visit their website at www.cancer.gov.

Testicular cancer is one of the most treatable cancers.

The survival rate for men with early-stage seminoma (the least aggressive type of testicular cancer) is greater than 95%. The disease-free survival rate for Stage II and III cancers is slightly lower, depending on the size of the tumor and when treatment is begun.

Testicular cancer may spread to other parts of the body. The most common sites include the:

• Abdomen
• Lungs
• Retroperitoneal area (the area near the kidneys)
• Spine

Complications of surgery can include:

• Infertility (if both testicles are removed)
• Damage to nerves that control erection, leading to impotence

If you are of childbearing age, ask your doctor about nerve-sparing surgery and methods to save your sperm for use at a later date.

Call your health care provider if you have symptoms of testicular cancer.

There is no known effective screening technique for testicular cancer. However, a testicular self-examination (TSE) performed on a monthly basis may help in detecting such cancer at an early stage, before it spreads. Finding it early is important to successful treatment and survival. Young men are often taught how to perform such exams shortly after puberty.

U.S. Preventive Services Task Force (USPSTF). Screening for testicular cancer: recommendation statement. Rockville (MD): Agency for Healthcare Research and Quality (AHRQ); 2004 Feb. 2 p.