Neurotropism as a prognostic factor in cutaneous melanoma patients.

Abstract

Neurotropism is a feature that is encountered rarely in melanoma and is considered to be associated with increased risk of local recurrence. However, its prognostic significance still remains controversial. The objective of this study was to determine the clinical significance of neurotropism in cutaneous melanoma patients. A total of 519 cutaneous melanoma patients were enrolled into this study and their data were analyzed in a retrospective fashion. The melanomas without neurotropism (n=496; 95.6%) were larger in number than those with neurotropism (n=23; 4.4%). Compared to non-neurotropic melanomas, neurotropic melanomas were more likely localized in the extremities (p=0.007) and they were more frequently associated with non-superficial spreading histologic subtype (p=0.029), advanced Clark invasion level (IV-V) (p=0.007), thick Breslow depth (p=0.001), high mitotic rate (p=0.041), ulcerated lesions (p<0.001), lymphovascular invasion (p<0.001), and lymph node metastasis (p=0.013). The neurotropic melanomas were significantly associated with both unfavorable relapse-free survival (RFS) (p=0.045) and overall survival (OS) (p<0.001). However, neurotropism lost its prognostic significance in both RFS (p=0.767) and OS (p=0.644) in multivariable analyses. In conclusion, the presence of neurotropism predicts a greater risk for nodal involvement and is associated with worse survival in patients with cutaneous malignant melanoma, on the other hand it is not an independent risk factor when other powerful prognostic variables are considered.