Open Access Research article

Prediction of melanoma metastasis by the Shields index based on lymphatic vessel density

Maxine S Emmett1, Kirsty E Symonds1, Howard Rigby2, Martin G Cook3, Rebecca Price2, Chris Metcalfe4, Antonio Orlando5 and David O Bates1*

Author Affiliations

1 Microvascular Research Laboratories, Bristol Heart Institute, Department of Physiology and Pharmacology, University of Bristol, Bristol, UK

2 Department of Pathology, Frenchay Hospital, Bristol. UK

3 Royal Surrey County Hospital and University of Surrey, Guildford, UK

4 Department of Social Medicine, University of Bristol, Bristol, UK

5 Department of Plastic Surgery Frenchay Hospital, Bristol, UK

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BMC Cancer 2010, 10:208  doi:10.1186/1471-2407-10-208

Published: 17 May 2010

Abstract

Background

Melanoma usually presents as an initial skin lesion without evidence of metastasis. A significant proportion of patients develop subsequent local, regional or distant metastasis, sometimes many years after the initial lesion was removed. The current most effective staging method to identify early regional metastasis is sentinel lymph node biopsy (SLNB), which is invasive, not without morbidity and, while improving staging, may not improve overall survival. Lymphatic density, Breslow's thickness and the presence or absence of lymphatic invasion combined has been proposed to be a prognostic index of metastasis, by Shields et al in a patient group.

Methods

Here we undertook a retrospective analysis of 102 malignant melanomas from patients with more than five years follow-up to evaluate the Shields' index and compare with existing indicators.

Results

The Shields' index accurately predicted outcome in 90% of patients with metastases and 84% without metastases. For these, the Shields index was more predictive than thickness or lymphatic density. Alternate lymphatic measurement (hot spot analysis) was also effective when combined into the Shields index in a cohort of 24 patients.

Conclusions

These results show the Shields index, a non-invasive analysis based on immunohistochemistry of lymphatics surrounding primary lesions that can accurately predict outcome, is a simple, useful prognostic tool in malignant melanoma.