If a suspicious mole or other skin lesion has been removed and examination reveals it to be a melanoma, the removed tissue is further analyzed.
The results often include a number in millimeters, for example, 0.6 mm or 1.4 mm. This number is called the Breslow thickness.
Simply put, it indicates how deeply the melanoma has grown into the skin.
This depth is different from the size of the lesion visible on the surface. A melanoma can be small on the surface but still grow deeper into the skin. Conversely, a larger lesion can be relatively superficial.
Why is this depth important?
A melanoma originates from pigment cells in the skin. The deeper the melanoma has grown into the skin, the greater the risk of melanoma cells spreading.
Therefore, Breslow thickness is an important part of the results. Generally, the thinner the melanoma, the more favorable the prognosis tends to be.
However, Breslow thickness alone does not predict exactly what will happen to an individual. Doctors always consider multiple characteristics together.
Which thicknesses are used?
To assess the results, doctors look at, among other things, the thickness of the melanoma:
– up to 1 mm
– more than 1 to 2 mm
– more than 2 to 4 mm
– more than 4 mm
This classification helps doctors assess the melanoma and determine appropriate next steps.
Ulceration is also considered
In your results, in addition to Breslow thickness, you may encounter the word ulceration.
Ulceration means that there is a break or damage in the skin over the melanoma.
Why do doctors look at this? If no ulceration is found, it is generally more favorable. Ulceration is associated with a higher risk of the melanoma spreading.
Therefore, doctors not only look at how deeply the melanoma has grown but also whether ulceration is present. Together, this information helps doctors determine which follow-up steps are necessary.
Is Breslow thickness the same as staging?
No.
Breslow thickness indicates how deeply the melanoma has grown into the skin.
For staging, doctors consider multiple factors together, such as:
– the depth of the melanoma
– whether ulceration is present
– whether melanoma cells have been found in a lymph node
– whether the melanoma has spread further in the body
Breslow thickness is therefore one part of the overall picture.
In this article, we will focus on Breslow thickness. In a separate article, we will explain in more detail how the stage of a melanoma is determined.
Does Breslow thickness influence further testing?
Yes.
The depth of the melanoma helps doctors determine whether additional testing is needed.
For melanomas measuring approximately 0.8 mm or more, for example, doctors may discuss whether a sentinel lymph node biopsy is appropriate. Other characteristics of the melanoma also play a role.
In a separate article, we explain what the sentinel lymph node is and what to expect from this procedure.
What does Breslow thickness ultimately indicate?
Breslow thickness indicates how deeply the melanoma has grown into the skin. This information helps doctors assess risk and determine any necessary follow-up steps.
Breslow thickness never stands alone. Other characteristics of the melanoma and the results of any additional tests also matter.
