Prognostic factors of cutaneous melanoma in relation to metastasis at the sentinel lymph node: a case-controlled study.

BACKGROUND: The selection of patients who will undergo sentinel lymph node biopsy is primarily based on the histopathologic features of cutaneous melanoma. The purpose of this study is to identify prognostic factors that predict the sentinel lymph node metastasis in melanoma.
METHODS: Sixty-nine melanoma patients underwent sentinel lymph node biopsy at Padova Plastic Surgery Institute. Univariate chi-square and multivariate logistic regression analyses were conducted to identify the relationship between prognostic factors and positive sentinel lymph node. A Receiver Operating Characteristics (ROC) Curve was performed to identify the ideal Breslow thickness cutpoint at which to perform sentinel node biopsy.
RESULTS: Eleven of the 69 patients (16%) had sentinel lymph node metastases. By univariate analyses Breslow's thickness (p=0.001), ulceration (p=0.001), and lymphovascular invasion (p<0.0001) were found to be significant prognostic factors for the prediction of sentinel node micrometastases. The ROC Curve identified a Breslow thickness of 1.19 mm to be the most suitable cutpoint for sentinel lymph node positivity (p=0.003, sensibility 80%, specificity 69.6%).
CONCLUSIONS: Patients with Breslow thickness >or=1.19 mm, ulceration, and lymphovascular invasion are at higher risk for occult lymph node metastases. In addition it is important to use multiple selection criteria when performing sentinel lymph node biopsy especially in patients with thin melanomas.