What is testicular cancer?

Testicular cancer is when abnormal cells in a testicle start to divide and grow in an uncontrolled way. The testicles are part of the male reproductive system. 

The testicles

The testicles are two small oval shaped organs which hang below the penis in a pouch of skin called the scrotum.

Diagram of the testicles


From the age of puberty the testicles produce sperm.

The collecting tubules inside the testicle join together to form a tube called the epididymis. This tube carries on and gets wider as it leaves the testicle. The wider tube is called the spermatic cord.

The spermatic cord forms a short tube called the ejaculatory duct. This duct opens into the urethra (the tube from the bladder to the end of the penis).


The testicles produce the hormone testosterone. Testosterone develops male qualities like:

  • a deep voice
  • beard growth
  • muscle development
  • the ability to have an erection
  • male sex drive (libido)

    This video shows you different parts of the male reproductive system. It lasts for 1 minute and forty seconds.  

    Where does testicular cancer start?

    The testicles are made up of different types of cells. The type of cancer you have depends on the type of cell the cancer starts in.

    Most testicular cancers develop in germ cells. These are the cells that make sperm. Doctors put cancers that develop from germ cells into 2 main categories:

    • seminoma
    • non seminoma 

    Testicular cancer and the lymph nodes

    Lymph nodes  are part of the lymphatic system that runs throughout the body. The lymph nodes and lymph vessels contain a yellow fluid called lymph that flows through the lymphatic system. It collects waste products and drains into veins for the waste to be removed. 

    Cancer can spread to the lymph nodes and make them bigger (enlarged). It is common for testicular cancer to spread to the lymph nodes in the back of the tummy (abdomen). These are called the retroperitoneal lymph nodes.

    These lymph nodes are behind your bowel and just in front of your spine. They run alongside the major blood vessel in the abdomen (the aorta and the inferior vena cava).

    Diagram showing retroperitoneal lymph nodes

    How common is it?

    Although testicular cancer is rare, it is the most common cancer in men aged between 15 and 49. In the UK around 2,400 men are diagnosed with testicular cancer each year. 

    Who gets it?

    Younger men are more likely to get testicular cancer.

    Trans women can also develop testicular cancer if they haven't had an operation to remove their testicles (orchidectomy).

    Men in their early 30s are the most likely to get it. It then becomes less common as men get older.

    Last reviewed: 
    06 Feb 2022
    Next review due: 
    06 Feb 2025

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