Tumor growth rate as a prognostic factor of acral melanoma in a Korean population.

Rapid growth of cutaneous melanoma is associated with aggressive histopathologic features and poor prognosis. However, the impact of growth rate (GR) in acral melanoma (AM) remains largely unknown.We performed this study to identify the impact of GR on lymph node metastasis and survival in AM.We analyzed cases of invasive AM diagnosed at our institution between 1998 and 2017. We investigated the impact of GR on the prognosis of AM.A total of 126 cases of invasive AM were included. Log (GR) was significant associated with lymph node metastasis in the univariate logistic regression analysis (P = .005). The log-rank test revealed statistically significant differences in disease-free survival (DFS) and disease-specific survival (DSS) among the GR quartiles. In the Cox regression analysis, log (GR) was an independent predictor for DFS (P = .041), but not for DSS in multivariate analysis. In the subgroup analysis, log (GR) was an independent predictor for early-stage (≤2A) AM (DFS, P = .002; DSS, P = .004).The limitations of this study include the retrospective design of the study and possible recall bias.Our results suggest that GR is an important prognostic factor for DFS and DSS in AM patients and an independent predictor for early-stage AM.