LB1598 The impact of tumor growth rate on survival of acral melanoma

Abstract

Rapid growth of malignant melanoma is associated with aggressive histopathologic features, and poor prognosis in cutaneous melanoma. However, the impact of the growth rate (GR) on lymph node (LN) metastasis and survival in acral melanoma (AM) has not been investigated. We conducted this study to identify the influence of GR on LN metastasis and survival in AM. We analyzed data of invasive AM patients who underwent surgery at our institution over a period of 20 years. GR was calculated as the ratio of Breslow thickness to delay to operation from disease onset. Log scale [Log (GR)] was used for statistical analysis.In total, 126 cases were included (63 male, 63 female; median age 62.5 years, range: 30-83 years). Log (GR) was a significant predictor for LN metastasis in univariate logistic regression (P = .005); however not in multivariate logistic regression (P = .246). Log (GR) was a significant predictor for DFS (P < .001) and DSS (P < .001) in univariate Cox analysis but not after adjustment for LN metastasis (P = .061 for DFS; P = .108 for DSS). When we performed stratification analysis for stages, Log (GR) was significant for early stages of AM (≤2A) in multivariate Cox analysis (P = .024 for DFS; P = .008 for DSS). In conclusion, our results suggest GR is an important prognostic factor for DFS and DSS in AM.