Testicular cancers are malignancies that develop in one or both of the testicles. The testicles (or testes) are two egg-shaped glands of the male reproductive system that sit outside of the body in a skin sac called the scrotum.
The testicles are responsible for the production and storage of sperm, the male gamete (reproductive cell) that swims to fertilise the female gamete, called ova or eggs. They are also responsible for producing and secreting testosterone, the primary male hormone. Testosterone is responsible for the regulation of sexual development (including development of male reproductive organs, and secondary sex characteristics such as facial hair and voice deepening), bone and muscle mass, fat distribution, sex drive (or libido), sperm production and red blood cell production.
Testicular cancers are generally diagnosed in men between the ages of 25-40, however, it can affect anyone with testicles – including men, teenagers, transgender women, non-binary individuals, and intersex people – at any age.
Types of Testicular Cancers
There are several types of testicular cancers, which are categorised by the types of cells they develop from.
Germ Cell Tumours
Germ cell tumours are a rare group of neoplasms that arise from primordial germ cells – the cells responsible for developing into reproductive cells (gametes) such as ovum and sperm. These tumours typically originate in the gonads, which are the organs that produce gametes (ovaries in females and the testicles in males). These tumours are referred to as gonadal germ cell tumours. In some cases, germ cells can migrate to other parts of the body during early embryonic development, leading to tumour formation outside of the gonads later in life. These are known as extragonadal germ cell tumours, and are most commonly found in the brain, mediastinum, retroperitoneum, or sacrococcygeal region.
The most common types of germ-cell tumours that develop in the testicles include:
- Seminoma (most common).
- Embryonal carcinoma.
- Choriocarcinoma.
- Yolk sac tumours/Endodermal sinus tumours.
- Teratoma.
- Mixed germ-cell tumours.
Stromal Tumours
Stromal tumours are cancers that originate from the supportive hormone-producing tissues of the testicles, called the stroma. They are very rare, and develop from Sertoli and Leydig cells, which are support cells in the male reproductive system.
Sertoli-Leydig cell tumours are cancers that produces male hormones, such as testosterone. These types of tumours are often benign (non-cancerous) and slow growing, however, in rare instances they can be cancerous. Malignant (cancerous) Sertoli-Leydig cell tumours usually don’t respond well to chemotherapy and radiation therapy, and may have a poorer prognosis than other testicular cancers.
Intratubular Germ Cell Neoplasias (ITGCNs)
Intratubular germ-cell neoplasias (ITGCNs) is a condition where cells in the testicles look abnormal, but they haven’t spread beyond their point of origin. While this condition is not a malignancy, there is a high risk that it can transform into a form of testicular cancer. ITGCN is considered rare, and is often difficult to diagnose.
Testicular Neuroendocrine Tumours
Testicular neuroendocrine tumours (TNETs), also known as testicular carcinoid tumours, are a very rare form of cancer that develops in the testicles. For more information on TNETs, please refer to the Rare Cancers Australia Testicular Neuroendocrine Tumours page.
Treatment
If testicular cancer is detected, it will be staged and graded based on size, metastasis (whether the cancer has spread to other parts of the body) and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you.
Cancers can be staged using the TNM staging system:
- T (tumour) indicates the size and depth of the tumour.
- N (node) indicates whether the cancer has spread to nearby lymph nodes.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissue.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localised cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advanced or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Grade I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including location, stage of disease and overall health.
Treatment options for testicular cancer may include:
- Surgery, potentially including:
- Unilateral orchidectomy /orchiectomy.
- Bilateral orchidectomy /orchiectomy.
- Lymphadenectomy.
- Testicular prosthetic surgery.
- Radiation therapy.
- Chemotherapy.
- Watch and wait (for early-stage testicular cancers or after an orchidectomy).
- Clinical trials.
- Palliative care.
Testicular Cancer Treatment and Fertility
Treatment for testicular cancer may make it difficult to conceive a child. If fertility is important to you, discuss your options with your doctor and a fertility specialist prior to the commencement of treatment.
Risk factors
While the cause of testicular cancer remains unknown, the following factors may increase the risk of developing the disease:
- Having a personal history of testicular cancer.
- Having a family history of testicular cancer.
- Being infertile.
- Having certain conditions, such as
- Human immunodeficiency virus (HIV).
- Acquired immunodeficiency syndrome (AIDS).
- Cryptorchidism (undescended testicle(s)).
- Hypospadias (penile abnormality).
- Inguinal hernia (lump in the groin – repaired or not repaired).
Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned.
Symptoms
In some cases, testicular cancers appear asymptomatic.
Common symptoms of testicular cancer may include:
- A painless swelling in the testicle(s).
- A lump in the testicle(s).
- Changes in testicular size and/or shape.
- A feeling of heaviness in the scrotum.
- A feeling of unevenness in the scrotum.
- Pain or discomfort in the testicle(s) and/or scrotum.
- Fluid build-up in the scrotum.
- Aches in the lower abdomen, testicle(s) and/or scrotum.
- Back pain.
- Enlargement and/or tenderness of breast tissue caused by excess hormones.
Not everyone with the symptoms above will have cancer but see your general practitioner (GP) if you are concerned.
Diagnosis
If your doctor suspects you have testicular cancer, they may order the following tests to confirm the diagnosis and refer you to a specialist for treatment:
- Physical examination.
- Imaging tests, most commonly an ultrasound.
- Blood tests.
- Exploratory surgery.
Exploratory Surgery
After conducting the previously mentioned diagnostic tests, your doctor may strongly suspect that you have a testicular cancer. In most cases, a diagnosis can be confirmed after a biopsy, where a section of tissue is removed and analysed for cancer cells. However, doctors avoid conducting a biopsy in patients who have suspected testicular cancer as there is a small risk that making an incision in the scrotum could cause cancer cells to spread. As such, the only way to confirm the diagnosis safely is to perform a unilateral orchidectomy.
Once the testicle has been removed, it will be sent to a laboratory and analysed for cancer cells.
