The stage of a cancer describes its size and whether it has spread beyond the area of the body where it started. There are several staging systems for testicular cancer. Knowing the extent of the cancer and the type of cell involved helps the doctors decide on the most appropriate treatment.

A staging system commonly used in the UK, called the TNM system, is described here:

• T refers to the tumour size.
• N refers to whether lymph nodes are affected.
• M refers to whether cancer has spread to other parts of the body (metastases).

Tumour size (T)

• TIS (testicular carcinoma in situ) Cancer cells are present within the tubules of the testes but have not moved into the surrounding tissue of the testicle.
• T1 The tumour is only in the testicle and epididymis.
• T2 The tumour has started to grow into blood vessels or lymph nodes close to the testicle.
• T3 The tumour has grown as far as the spermatic cord (and possibly also the blood vessels or lymph nodes).
• T4 The tumour has grown into the scrotum.

Lymph nodes (N)

The N refers to whether the cancer cells have spread into the lymph nodes nearby and, if so, what size of lymph node is affected (some are larger than others). If lymph nodes are affected they are said to be positive.

• N0 The lymph nodes have no cancer cells.
• N1 The lymph nodes affected are smaller than 2cm wide.
• N2 At least one affected lymph node is larger than 2cm but smaller than 5cm wide.
• N3 At least one affected lymph node is bigger than 5cm wide.

Metastases (M)

Metastases refer to how far the cancer has spread.

• M0 The cancer does not appear to have spread to other organs.
• M1a The cancer has spread to the lungs or to distant lymph nodes (those furthest away from the testicles such as the collarbone).
• M1b Other organs are affected; for example the brain or the liver.

Doctors also take into account the levels of tumour markers, whether the cancer has spread into the chest area and whether it has spread into soft tissues of the body other than the lung.