Cancer of the testicles, also known as testicular cancer, is an uncommon type of cancer that primarily affects younger men.
The most common symptom of testicular cancer is a painless lump or swelling in the testicles. Other symptoms can include:
- a dull ache in the scrotum (the sac of skin that hangs underneath the penis and contains the testicles)
- a feeling of heaviness in the scrotum
The testicles are the two oval-shaped male sex organs that sit inside the scrotum on either side of the penis. The testicles are an important part of the male reproductive system because they produce sperm and the hormone testosterone, which plays a major role in male sexual development.
Types of testicular cancer
The different types of testicular cancer are classified by what type of cells the cancer first begins in.
The most common type of testicular cancer is known as ‘germ cell testicular cancer’, which accounts for around 95% of all cases. Germ cells are a type of cell that the body uses to help create sperm.
There are two main subtypes of germ cell testicular cancer. They are:
- seminomas, which account for 40% of all cases of testicular cancer
- non-seminomas, which account for the remaining 60% of cases of testicular cancer
In practical terms, the only important difference between the two subtypes is that seminomas tend to respond better to radiotherapy (treatment that uses radiation to kill cancer cells) and non-seminomas tend to respond better to chemotherapy (treatment that uses medication to kill cancer cells).
Less common types of testicular cancer include:
- Leydig cell tumours, which account for around 1-3% of cases
- Sertoli cell tumours, which account for around 1% of cases
This article focuses on germ cell testicular cancer. The Macmillan website has more information about Leydig cell tumour and Sertoli cell tumour.
How common is testicular cancer?
Testicular cancer is relatively uncommon, accounting for just 1% of all cancers that occur in men. Each year in England, it is estimated that there are three to six new cases of testicular cancer for every 100,000 men.
Testicular cancer is unusual compared to other types of cancers because it tends to affect younger men who are 20 to 55 years of age. As a result, although relatively uncommon overall, testicular cancer is the most common type of cancer to affect young men (20 to 35 years of age).
Rates of testicular cancer are five times higher in white men than in black men. The reasons for this are unclear.
The number of cases of testicular cancer that are diagnosed each year has roughly doubled over the last two decades, both in England and in other European and North American nations. On the other hand, testicular cancer is virtually unheard of in some African and Asian nations. Again, the reasons for this are unclear.
The cause or causes of testicular cancer are unknown, but a number of risk factors have been identified that increase the chance of developing the condition. These include:
- having a family history of testicular cancer
- being infertile
- being born with undescended testicles (cryptorchidism). About 3-5% of boys are born with their testicles located inside their abdomen, which usually descend into the scrotum during the first four months of life
The outlook for testicular cancer is very good because it is one of the most treatable types of cancer. Over 95% of men with early stage testicular cancer will be completely cured.
Even cases of advanced testicular cancer, where the cancer has spread outside the testicles to nearby tissue, have an 80% chance of being cured.
Compared to other cancers, deaths from testicular cancer are rare. For example, in 2008, 60 deaths were caused by testicular cancer in England and Wales.
Treatment for testicular cancer includes the surgical removal of the affected testicle (which should not affect fertility or the ability to have sex), chemotherapy and radiotherapy.