The Impact on Final Breslow Thickness and Sentinel Lymph Node Status with Initial Biopsies of Cutaneous Melanomas Transected at the Base
Atin Agarwal, Carlos A Torres-Cabala, Michael T Tetzlaff, David L Stockman, Vicki Chu, Victor G Prieto, Jonathan L Curry. Baylor College of Medicine, Houston, TX; University of Texas MD Anderson Cancer Center, Houston, TX
Background: The histologic evaluation of primary tumor characteristics (Breslow thickness (BT), mitotic rate (MR), ulceration) in cutaneous melanoma is critical for staging and classification, prognosis and clinical management decisions. BT is a strong and consistent histologic parameter of sentinel lymph node (SLN) status. Melanomas that are superficially sampled with tumor cells present at the deep tissue edge may underestimate true BT, pose a risk for positive SLNB, and provide inaccurate prognostic information. We report the impact of positive deep margins on initial biopsies of cutaneous melanoma with respect to final BT on wide local excision (WLE) and outcome of SLNB.
Design: An eighteen month retrospective review was performed in patients diagnosed with primary cutaneous melanoma who undergone WLE and SLNB. Patients were categorized into four groups according to status of deep margin on initial biopsy and outcome of SLNB. G1=absence of positive deep margin and negative SLNB, G2=absence of positive deep margin and positive SLNB, G3=positive deep margin and negative SLNB, G4=positive deep margin and positive SLNB. Comparisons between groups were made with Kruskal Wallis test. Statistical significance was considered at p <0.05.
Results: 171 patients fulfilled the criteria and were distributed into the four categories as follows: G1 (70), G2 (31) G3 (51), G4 (19). Groups with positive SLNB (G2 & G4) had greater final BT than patients with negative SLNB (G1 & G3) regardless of the status of deep tissue edge on initial skin biopsy. The final BT in patients in G4 patients was significantly greater compared to the final BT in the other groups. G4 patients also had greater tumor deposit size in SLNB compared to G2 patients.
|CL median (range)||4 (2-5)||4 (4-5)||4 (2-5)||4 (3-5)|
|Initial BT mm* (range)||2.4(0.4-17)||3.12(0.54-15)||2.19(0.20-9.7)||2.86(0.57-5.0)|
|Final BT mm* (range)||2.55(0.44-17)||3.18(0.54-15)||2.60(0.20-9.7)||3.38(1.5-5.0)|
|Tumor deposit size (mm)* in SLN* (range)||NA||1.63(0.1-5.3)||NA||2.77(0.1-15)|