Male Reproductive Anatomy and Testicular Cancer

How is the Reproductive System Affected by Testicular Cancer?

The male reproductive system includes the testes, sperm ducts, prostate gland, urethra and penis. Unfortunately, just like many other tissues of the human body, cancers may develop from the reproductive system. Prostate cancer is by far the most common cancer of the male reproductive system followed by testicular cancers, which consist of several different  types. Testicular cancer arises from the testicles, also known as the testes, the plural form of testis.

The full name for the sperm cell is spermatozoon, plural spermatozoa. The sperm cell is different from most all other cells of the human body in that it is the only cell type which contains one set of chromosomes, whereas all other cells contain two sets of each chromosome. It combines with the egg, which has a single copy of the mother's chromosomes, resulting in a full set of chromosomes. This set of chromosomes accounts for the majority of the characteristics of the individual to be born.

Sperm pass through 3 main phases: production, storage and delivery.

PRODUCTION

The process of sperm creation is termed spermatogenesis. It occurs in a region of the testes known as the seminiferous tubules. Within the seminiferous tubules are found the spermatogonia cells from which the sperm cells are derived. As the sperm travel the seminiferous tubules, they are nourished and continue to mature. Around 200-400 million sperm are produced each day.

STORAGE

The sperm exit the seminiferous tubules and enter the epididymis, which is another tightly coiled tubular structure. Sperm continue to develop at this stage and are ultimately stored towards the end of the epididymis. It typically takes around 3 months for sperm to become fully mature.

DELIVERY

With adequate stimulation from the nervous system, smooth muscle contractions propel the sperm from epididymis into the vas deferens (also known as the ductus deferens) which loops around the bladder and passes into ejaculatory duct, which lies in the prostate gland.

This process is known as emission and happens immediately prior to ejaculation. Just before the ejaculatory duct, the seminal vesicle provides a nutrient-rich fluid which makes up the majority of the volume of the ejaculate. The prostate also contributes fluid which serves to lower the pH and protect the sperm. From there the sperm, now known as semen since it has fluid from the seminal vesicles, is ejected down the urethra and out the penis. A sphincter muscle around the urethra in the prostate contracts to prevent the sperm from going the wrong direction into the bladder.

APPLICATIONS TO TESTICULAR CANCER

POSSIBLE CHANGES BEFORE ANY TREATMENT

Some studies have suggested that men with testicular cancer have evidence of impaired spermatogenesis even before treatment. The exact reason for this has been unclear, but may be related to the underlying factors which caused the testicular cancer in the first place, such as cryptochidism

POSSIBLE CHANGES FOLLOWING CHEMOTHERAPY OR RADIATION THERAPY

Both chemotherapy and radiation therapy can disrupt spermatogenesis. The higher the dose of chemotherapy, the greater the risk for permanent infertility.

POSSIBLE CHANGES FOLLOWING RETROPERITONEAL LYMPH NODE DISSECTION

Retroperitoneal lymph node dissection is the surgical removal of the lymph nodes in the abdomen that drain the lymph contents from the testes. This is the first place most testicular cancers spread and surgery can be an important part to curing the cancer. The nerves responsible for the coordinated process of ejaculation pass from the spinal cord through this region. These nerves can be affected by surgery resulting in a condition known as retrograde ejaculation. As mentioned above, during ejaculation, a sphincter muscle contracts just before the bladder, preventing the semen from going the wrong direction (retrograde) into the bladder instead of down the urethra through the penis. In retrograde ejaculation, the nerve responsible for the sphincter contraction does not function correctly so semen enters the bladder resulting in what is oftentimes known as a "dry orgasm". 

Any of the treatments for testicular cancer can potentially result in infertility. Sperm banking should be considered in anyone wanting to father children following treatment.

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