Onkológia 6/2016

Sentinel lymph node in melanoma

Melanoma is highly malignant tumor which arises through malignant transformation of melanocytes. The cornerstone of melanoma treatment is a wide excision in an early stage of the disease and intervention in regional lymfatic drainage by performing sentinel node biopsy and completion lymph node dissection in case of metastatic sentinel nodes. Purpose: The aim of this study is to evaluate impact of Clark‘ s depth of invasion, Breslow thickness, mitotic index and proliferation index Ki67 on metastatic involvement of sentinel nodes and to compare these results with data known from literature. Patients and methods: In our study, 219 patients who underwent surgery for melanoma and sentinel biopsy between 1.1.2012 and 31.12.2013 were included. This study is a retrospective observational study. The data were evaluated by statistical software SPSS, version 19.0. Results: We confirmed in accordance with literature statistical significance of impact of Clark‘ s depth of invasion and Breslow thickness on metastatic involvement of sentinel nodes. On contrary to literature, we did not confirm statistically significant association of mitotic index and Ki67 with metastatic sentinel node involvement. These statistic tests were very limited by a very small number of available data of mitotic index and Ki67 in histopathological findings. Conclusion: Our results demonstrate a need for standardization of histopathological protocol for melanoma and also sentinel nodes at our department. We currently consider the evaluation of mitotic index and Ki67 in melanoma histopathological protocol as inevitable. We recommend to include micromorphometric parameters of metastatic deposits into evaluation of micrometastasis in sentinel nodes in future. Assessment of micromorphometric parameters could in future contribute to determination of such sentinel node tumor burden which would allow to spare patients of complete lymphadenectomy. Current prognostic and diagnostic value of sentinel node biopsy would thus gain even more important therapeutic value.

Keywords: melanoma, sentinel node biopsy, sentinel node, mitotic index, micromorphometric parameters