Lymphatic invasion identified by monoclonal antibody D2-40, younger age, and ulceration: predictors of sentinel lymph node involvement in primary cutaneous melanoma.

OBJECTIVES: To assess whether lymphatic invasion identified by immunostaining with monoclonal antibody (Mab) D2-40 in primary cutaneous melanomas correlates with other clinicopathologic factors and to assess whether lymphatic invasion is a potential predictor of sentinel lymph node (SLN) status.
DESIGN: Retrospective case-series study.
SETTING: Academic referral center. Patients Ninety-six consecutive patients with primary cutaneous melanomas 1 mm thick or greater with adequate pathologic material available for immunohistochemical studies and SLN biopsy. MAIN OUTCOME MEASURES: Association between lymphatic invasion identified by immunostaining with Mab D2-40 in primary cutaneous melanoma and correlation with the clinicopathologic features and the association of all of the factors with SLN status.
RESULTS: Lymphatic invasion identified by immunostaining with Mab D2-40 was significantly associated with deeper Clark level of invasion (P < .001), and greater Breslow tumor thickness (P = .01) SLN positivity was identified in 23 of 96 cases (24%). At univariate analysis, younger age (P = .03), ulceration (P < .006), lymphatic invasion (P < .02), deeper Clark level of invasion (P < .008), Breslow tumor thickness (P = .008), and tumor site on the trunk (P = .02) were significantly associated with SLN metastases. At multivariate analysis, only younger age (P = .04), ulceration (P = .03), and lymphatic invasion detected by immunostaining with Mab D2-40 (P = .01) were significantly associated with SLN positivity. The probability of SLN positivity was 13% when all 3 independent prognostic factors yielded negative findings and increased to 61% when all 3 variables yielded positive findings.
CONCLUSIONS: Breslow tumor thickness, Clark level of invasion, and tumor site on the trunk predicted SLN status at univariate analysis. Multivariate regression analysis showed that lymphatic invasion identified by immunostaining with Mab D2-40, younger age, and ulceration were the only independent prognostic factors. The most significant predictor of SLN metastasis was the positivity of all 3 independent prognostic factors (61%). Findings of this study suggest that assessment of lymphatic invasion by immunostaining with Mab D2-40 with other clinicopathologic factors can be used to identify patients who could be spared the need for SLN biopsy.