[462] Percentage of Sentinel Lymph Node Involvement by Metastatic Melanoma as Measured by ACIS Cytometric Image Analysis Is Associated with Survival

S Lauer, R Yaar, A Page, A Hestley, K Delman, G Carlson, C Cohen. Emory University Hospital, Atlanta, GA

Background: Sentinel lymph node (SLN) biopsy is a common procedure for staging patients with melanoma. Immunohistochemistry for MelanA and HMB45 facilitates examination of SLNs by highlighting small metastases. Previous studies suggest that increased volume of metastatic melanoma in SLNs may be a prognostic factor associated with adverse outcomes. Cytometric image analysis with the ACIS system may be useful for quantitating the amount of melanoma metastasis in SLNs. We aim to quantitate the percentage of SLN involvement by metastatic melanoma using the ACIS system, and to identify a relationship between the %SLN involvement, survival and recurrence.
Design: MelanA and HMB45 stained sections of SLNs from 119 patients with melanoma and a single positive SLN were reviewed, scanned and analyzed using the ACIS digital imaging system. The %SLN involvement was calculated by dividing the area staining positively for MelanA and HMB45 by the total lymph node area. The %SLN involvement was compared to clinical data for survival, recurrence, Breslow depth, and ulceration.
Results: Metastases stained positively for MelanA and HMB45 in 99.2% and 96.6% of cases. At a mean clinical follow-up time of 82 months, there were a total of 41 recurrences (39%) and 34 deaths (32.4%). Using HMB45 immunostaining, >5% SLN involvement was significantly associated with decreased survival (59.3% vs 77.8%, p=.047). Increased risk of recurrence approached significance (47.5% vs 28.9%, p=.055). Using MelanA staining, >10% SLN involvement was significantly associated with decreased survival (47.8% vs 72.1%, p=.03), while increased risk of recurrence approached significance (56.5% vs 36.0%, p=.07). No difference in survival or recurrence was identified when using a cutoff of >10% for HMB45 and >5% for MelanA. The %SLN involvement was not associated with Breslow depth or ulceration. A head and neck primary site was associated with a higher %SLN involvement compared to all anatomic sites (22.3% vs 12.51%, p=0.02).
Conclusions: Increased %SLN involvement by metastatic melanoma as measured by ACIS image cytometry of HMB45 and MelanA staining is significantly associated with decreased survival. Increased risk of recurrence also approached significance with higher percentages of SLN involvement. These findings suggest that %SLN involvement may be a useful prognostic parameter in melanoma patients with single positive SLN metastases.
Category: Dermatopathology

Monday, March 9, 2009 9:30 AM

Poster Session I Stowell-Orbison/Autopsy Award # 76, Monday Morning