Number of levels required to assess Breslow thickness in cutaneous invasive melanoma: An observational study

Melanoma is a globally significant and highly prevalent disease, with Breslow thickness widely recognized as the most important histologic indicator of prognosis. In the newest edition of the AJCC Cancer Staging Manual, changes have been made to the definition of stages based on Breslow thickness. It is therefore imperative we accurately measure the Breslow thickness in a standardized fashion.

Our study aimed to identify the optimal number of levels required to measure Breslow thickness. We reviewed archived cases of previously diagnosed invasive melanomas and assessed whether there was a change of T stage with the greater number of levels examined.

In our series of 54 cases, 10 (18.5%) cases were upgraded as additional levels were examined, statistically significant at the threshold of three levels.

Our data suggests the optimal number of levels to examine is 3, with no benefit seen in further levels up to 10.