Effect of changes in Breslow thickness between the initial punch biopsy results and final pathology reports in acral lentiginous melanoma patients

Acral lentiginous melanoma (ALM) is the most common subtype of cutaneous melanoma among Asians; punch biopsy is widely performed for its diagnosis. However, the pathologic parameters evaluated via punch biopsy may not be sufficient for predicting disease prognosis compared to the parameters evaluated via excisional biopsy. We investigated whether changes in Breslow thickness (BT) between initial punch biopsy results and final pathology reports can affect the prognosis of ALM. Pathologic parameters were recorded from specimens acquired through the initial punch biopsy and wide excision. Patients were classified into two groups based on a change in Breslow depth: the BT increased or decreased on comparing the samples from the initial punch biopsy and final wide excision. We compared clinical characteristics, and a Cox regression model was used to identify independent prognostic factors influencing melanoma-specific death (MSD). Changes in BT did not affect MSD (hazard ratio [HR]: 0.55, P = 0.447). In multivariate analysis, a higher BT (> 2 mm) (HR: 9.93, P = 0.046) and nodal metastasis (HR: 5.66, P = 0.041) were significantly associated with an increased MSD risk. The use of punch biopsy did not affect MSD despite the inaccuracy of BT measurement as long as ALM was accurately diagnosed.