Fig 1. Schematic representation of the male reproductive system showing the position of testicles
Testicles (also called testes; a single testicle is called a testis) are part of the male reproductive system. The 2 organs are each normally a little smaller than a golf ball in adult males. They are held within a sac of skin called the scrotum. The scrotum hangs under the base of the penis.
Testicles have 2 main functions:
- They make male hormones (androgens) such as testosterone.
- They make sperm, the male cells needed to fertilize a female egg cell to start a pregnancy.
Causes of testicular cancer
It is not clear what causes testicular cancer in most cases.Healthy cells grow and divide in an orderly way to keep the body functioning normally. Cancer starts when cells begin to grow out of control. Cells in nearly any part of the body can become cancer and spread to other parts of the body. Cancer that starts in the testicles is called testicular cancer.The accumulating cells form a mass in the testicle.
Risk factors
Factors that may increase your risk of testicular cancer include:
- An undescended testicle (cryptorchidism).The testes form in the abdominal area during fetal development and usually descend into the scrotum before birth. Men who have a testicle that never descended are at greater risk of testicular cancer than are men whose testicles descended normally. The risk remains elevated even if the testicle has been surgically relocated to the scrotum.
- Abnormal testicle development.Conditions that cause testicles to develop abnormally, such as Klinefelter syndrome(also known as 47, XXY or XXY, is the set of symptoms that result from two or more X chromosomes in males. The primary features are infertility and small testicles), may increase your risk of testicular cancer.
- Family history.If family members have had testicular cancer, you may have an increased risk.
- Testicular cancer affects teens and younger men, particularly those between ages 15 and 35. However, it can occur at any age.
Symptoms
Fig 2. Normal testes and testes with cancer showing testicular lumps
Testicular lumps
Signs and symptoms of testicular cancer include:
- A lump or enlargement in either testicle
- A feeling of heaviness in the scrotum
- A dull ache in the abdomen or groin
- A sudden collection of fluid in the scrotum
- Pain or discomfort in a testicle or the scrotum
- Enlargement or tenderness of the breasts
- Back pain
- Cancer usually affects only one testicle.
Types of testicular cancer
1. Germ cell tumors
More than 90% of cancers of the testicle start in cells known as germ cells. These are the cells that make sperm.The main types of germ cell tumors (GCTs) in the testicles are seminomas and non-seminomas.These types occur about equally. Many testicular cancers contain both seminoma and non-seminoma cells. These mixed germ cell tumors are treated as non-seminomas because they grow and spread like non-seminomas.
1.1.Seminomas
Seminoma tumors occur in all age groups, but if an older man develops testicular cancer, it is more likely to be seminoma. Seminomas, in general, arenot as aggressive as non-seminomas.
1.2.Non-seminomas
These types of germ cell tumors usually occur in men between their late teens and early 30s. The four main types of non-seminoma tumors are embryonal carcinoma, yolk sac carcinoma, choriocarcinoma, and teratoma.
2. Carcinoma in situ of the testicle
Testicular germ cell cancers can start as a non-invasive form of the disease called carcinoma in situ (CIS) or intratubular germ cell neoplasia. In testicular CIS, the cells look abnormal under the microscope, but they have not yet spread outside the walls of the seminiferous tubules (where sperm cells are formed). Carcinoma in situ doesnot always progress to invasive cancer.
3. Stromal tumors
Tumors can also start in the supportive and hormone-producing tissues, or stroma, of the testicles. These tumors are known as gonadal stromal tumors. They make up less than 5% of adult testicular tumors, but up to 20% of childhood testicular tumors. The main types are Leydig cell tumors and Sertoli cell tumors.
3.1.Leydig cell tumors
These tumors start in the Leydig cells in the testicle that normally make male sex hormones (androgens like testosterone). Leydig cell tumors can develop in both adults and children. These tumors often make androgens (male hormones), but sometimes they make estrogens (female sex hormones).Most Leydig cell tumors are not cancerous. They seldom spread beyond the testicle and can often be cured with surgery. Still, a small number of Leydig cell tumors do spread to other parts of the body. These tend to have a poor outlook because they usually donot respond well to chemo or radiation therapy.
3.2.Sertoli cell tumors
These tumors start in normal Sertoli cells, which support and nourish the sperm-making germ cells. Like the Leydig cell tumors, these tumors are usually benign (non-cancerous) but if they spread, they usually donot respond well to chemo or radiation therapy.
4. Secondary testicular cancers
Cancers that start in another organ and then spread (metastasize) to the testicle are called secondary testicular cancers. These are not true testicular cancers, that is, they donot start in the testicles. They are named and treated based on where they started.
Lymphoma is the most common secondary testicular cancer. Testicular lymphoma is more common in men older than 50 than primary testicular tumors. The outlook depends on the type and stage of lymphoma. The usual treatment is surgical removal, followed by radiation and/or chemotherapy.
In boys with acute leukemia, the leukemia cells can sometimes form a tumor in the testicle. Along with chemotherapy to treat the leukemia, this might require treatment with radiation or surgery to remove the testicle.
Cancers of the prostate, lung, skin (melanoma), kidney, and other organs also can spread to the testicles. The outcome for these cancers tends to be poor because these cancers have usually spread widely to other organs as well. Treatment depends on the specific type of cancer.
Diagnosis
In some cases men discover testicular cancer themselves, either unintentionally or while doing a testicular self-examination to check for lumps. In other cases, your doctor may detect a lump during a routine physical exam.
To determine whether a lump is testicular cancer, your doctor may recommend:
- A testicular ultrasound test uses sound waves to create an image of the scrotum and testicles. During an ultrasound you lie on your back with your legs spread. Your doctor then applies a clear gel to your scrotum. A hand-held probe is moved over your scrotum to make the ultrasound image.An ultrasound test can help your doctor determine the nature of any testicular lumps, such as whether the lumps are solid or fluid-filled. An ultrasound also tells your doctor whether lumps are inside or outside of the testicle.
- Blood tests.Your doctor may order tests to determine the levels of tumor markers in your blood. Tumor markers are substances that occur normally in your blood, but the levels of these substances may be elevated in certain situations, including testicular cancer. A high level of a tumor marker in your blood doesnot mean that you have cancer, but it may help your doctor in determining your diagnosiseg.Some seminomas can increase blood levels of a protein called human chorionic gonadotropin (HCG). HCG can be checked with a simple blood test and is considered a tumor marker for certain types of testicular cancer. It can be used for the diagnosis and to check how the patient is responding to treatment.Embryonal carcinoma can increase blood levels of a tumor marker protein called alpha-fetoprotein (AFP), as well as human chorionic gonadotropin (HCG).
- Testicular biopsy.In order to determine if the lump on your testicle may be cancerous, a small piece of testicular tissue may be removed and analysed under a microscope (testicular biopsy). Testicular biopsy helps to determine if the lump is cancerous and, if so, what type of cancer.
Staging the cancer
Once your doctor confirms your diagnosis, the next step is to determine the extent (stage) of the cancer. To determine whether cancer has spread outside of your testicle, you may undergo:
- Computerized tomography (CT) scan.CT scans take a series of X-ray images of your abdomen, chest and pelvis. Your doctor uses CT scans to look for signs that cancer has spread.
- Blood tests.Blood tests to look for elevated tumor markers can help your doctor understand whether cancer likely remains in your body after your testicle is removed.
After these tests, your testicular cancer is assigned a stage. The stage helps determine what treatments are best for you.The stages of testicular cancer are indicated by Roman numerals that range from 0 to III, with the lowest stages indicating cancer that is limited to the area around the testicle. By stage III, the cancer is considered advanced and may have spread to other areas of the body, such as the lungs.
Treatment
Depending upon the stage of the testicular cancer, following treatment may be required:
- Surgery
- Radiation therapy
- Chemotherapy
- Surgery
Operations used to treat testicular cancer include:
- Surgery to remove your testicle(radical inguinal orchiectomy) is the primary treatment for nearly all stages and types of testicular cancer. To remove your testicle, your surgeon makes an incision in your groin and extracts the entire testicle through the opening. A prosthetic, saline-filled testicle can be inserted if you choose. In cases of early-stage testicular cancer, surgical removal of the testicle may be the only treatment needed.
- Surgery to remove nearby lymph nodes(retroperitoneal lymph node dissection) is performed through an incision in your abdomen. Your surgeon takes care to avoid damaging nerves surrounding the lymph nodes, but in some cases harm to the nerves may be unavoidable. Damaged nerves can cause difficulty with ejaculation, but won’t prevent you from having an erection.
If surgery is your only treatment for testicular cancer, your doctor will recommend a schedule of follow-up appointments. At these appointments, typically every few months for the first few years and then less frequently after that you will undergo blood tests, CT scans and other procedures to check for signs that your cancer has returned or not.
2. Radiation therapy
Radiation therapy uses high-powered energy beams, such as X-rays, to kill cancer cells. During radiation therapy, you are positioned on a table and a large machine moves around you, aiming the energy beams at precise points on your body.Radiation therapy may be recommended after surgery to remove your testicle.Side effects may include nausea and fatigue, as well as skin redness and irritation in your abdominal and groin areas. Radiation therapy is also likely to temporarily reduce sperm counts and may impact fertility in some men. Talk to your doctor about your options for preserving your sperm before beginning radiation therapy.
3. Chemotherapy
Chemotherapy treatment uses drugs to kill cancer cells. Chemotherapy drugs travel throughout your body to kill cancer cells that may have migrated from the original tumor.Chemotherapy may be your only treatment, or it may be recommended before or after lymph node removal surgery.Side effects of chemotherapy depend on the specific drugs being used.Common side effects include fatigue, nausea, hair loss and an increased risk of infection. There are medications and treatments available that reduce some of the side effects of chemotherapy.Chemotherapy may also lead to infertility in some men, which can be permanent in some cases. Talk to your doctor about your options for preserving your sperm before beginning chemotherapy.