The value of multi-marker reverse transcriptase-polymerase chain reaction (MM RT-PCR) assay in lymphatic drainage (LY) and peripheral blood (BL) for molecular staging of melanoma patients (pts) after lymph node dissection (LND)

8053 Background: We assessed the presence of melanoma cells in LY and BL in melanoma pts after LND with MM RT-PCR assay for the evaluation of disease outcomes. Methods: Between 05/2002 and 06/2005 we collected 24-hr LY in 207 stage III melanoma patients after radical LND (91 - completion LND after positive sentinel node biopsy - CLND and 116 - therapeutic LND for clinically/cytologically detected regional lymph node (LN) metastases - TLND). In 101 pts (since 02/2004) we have simultaneously collected a 5 ml sample of BL. In order to detect melanoma cells, RT-PCR assays with primers specific for tyrosinase, MART1 (MelanA) and uMAGE mRNA were applied. The drain fluid or BL sample was assumed to be positive if the presence of at least 1 marker was detected in the assay. Median follow-up time for survivors was 13 months (range: 4 - 39 months). Results: The LY MM RT-PCR assay results were positive in 57/207 pts (27.5%) - in 13 for tyrosinase only, in 17 for MART1 only, in 10 for uMAGE only, in 13 for a combination of the two markers and in 4 simultaneously for all three markers. We observed a significantly higher rate of recurrences in pts with positive LY MM RT-PCR results (44/57 cases; 77%) than in those with negative results (72/150 cases; 48%; p=0.0004). Positive results of the LY MM RT-PCR correlated with established predictive factors: the number of involved lymph nodes (p=0.03), extracapsular extension of LN metastases (p=0.004) and type of LND (CLND vs. TLND; p = 0.0004). We observed a significant relationship between positive LY MM RT-PCR results and shorter overall (OS) and disease free survival (DFS), both in univariate and multivariate analyses. In 107 pts, in whom the LY and BL MM RT-PCR assays were analyzed concurrently, we found positive results of the LY RT-PCR assay in 33 cases (32.7%) and the BL RT-PCR assay in 24 cases (23.7%) (17 of these positive results were detected in both tests), but longer follow-up time is necessary to perform a survival analysis in this group. Conclusions: We observed positive results of MM RT-PCR assay for melanoma cells in approximately 28% of LY after LND, which correlated significantly with early melanoma recurrences and shorter survival. No significant financial relationships to disclose.