Cancer of the testicle - Introduction

Cancer of the testicles, also known as testicular cancer, is one of the less common cancers. It usually affects younger men between the ages of 15 and 44.

The most common symptom 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

Read more about the symptoms of testicular cancer.

The testicles

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 the 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 around 40% of all germ cell testicular cancers
• non-seminomas, which account for around 60% of all germ cell testicular cancers

Seminomas and non-seminomas tend to respond well to chemotherapy, a treatment that uses medication given directly into the bloodstream 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 the UK around 2,090 men are diagnosed with testicular cancer, according to Cancer Research UK.

Testicular cancer is unusual compared to other cancers because it tends to affect younger men. As a result, although relatively uncommon overall, testicular cancer is the most common type of cancer to affect men between the ages of 15 and 44.

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 in the UK has roughly doubled since the mid-1970s. Again, the reasons for this are unclear.

Causes of testicular cancer

The cause or causes of testicular cancer are unknown, but a number of things have been identified that increase the chance of developing the condition. These include: