Surgical treatment of melanoma patients with early sentinel node involvement

Lymphadenectomy promotes tumor growth and cancer cell dissemination in the spontaneous RET mouse model of human uveal melanoma

Resection of infiltrated tumor-draining lymph nodes (TDLNs) is a standard practice for the treatment of several cancers including breast cancer and melanoma. However, many randomized prospective trials have failed to show convincing clinical benefits associated with LN removal and the role of TDLNs in cancer dissemination is poorly understood. Here, we found in a well-characterized spontaneous mouse model of uveal melanoma that the growth of the primary tumor was accompanied by increased lymphangiogenesis and cancer cell colonization in the LNs draining the eyes. But, unexpectedly, early resection of the TDLNs increased the growth of the primary tumor and associated blood vessels as well as promoted cancer cell survival and dissemination. These effects were accompanied by increased tumor cell proliferation and expression of phosphorylated AKT. Topical application of a broad anti-inflammatory agent, Tobradex, or an oral treatment with cyclooxygenase-2 specific inhibitor, Celecoxib, reversed tumor progression observed after complete lymphadenectomy. Our study confirms the importance of tumor homeostasis in cancer progression by showing the enhancing effects of TDLN removal on tumor growth and cancer cell dissemination, and suggests that TDLN resection may only be beneficial if used in combination with anti-inflammatory drugs such as Tobradex and Celecoxib.

Can SOX-10 or KBA.62 Replace S100 Protein in Immunohistochemical Evaluation of Sentinel Lymph Nodes for Metastatic Melanoma?

BACKGROUND

Microscopic evaluation of sentinel lymph nodes for metastatic melanoma relies, in part, on the use of immunohistochemical analysis to identify minute metastatic deposits that may be overlooked on routine microscopy. At present S100 protein is widely used in this role, in large part for its superior sensitivity; however, interpretation is hampered by the presence of benign S100 protein-positive cellular elements present in every lymph node, leading to reduced specificity and consequent difficulties in interpretation. In recent years, multiple melanocytic markers have emerged that promise superior sensitivity and specificity, including KBA.62 and SOX-10. SOX-10 shows a nuclear pattern of staining. In normal tissue it is expressed in Schwann cells, melanocytes, and myoepithelial cells of salivary, bronchial, and mammary glands. KBA.62 is also specific except for staining of endothelial cells and shows a membranous staining pattern. This study was undertaken to determine whether KBA.62 or SOX-10 could equal (or surpass) the sensitivity of S100 protein while offering superior specificity in the immunohistochemical evaluation of sentinel lymph nodes for metastatic melanoma.

DESIGN

In this study we performed immunohistochemical stains for S100 protein, Sox-10, and KBA.62 on 50 lymph nodes with proven metastatic melanoma.

RESULTS

SOX-10 detected all cases of metastatic melanoma (50 of 50 cases; 100%) compared with S100 protein (48 of 50 cases; 96%) and KBA.62 (37 of 50 cases; 74%). There was no "background" staining of normal cellular elements with SOX-10 or KBA.62. In contrast, S100 protein was expressed in scattered dendritic interdigitating reticulum cells in the paracortex of lymph nodes, showing cytoplasmic and nuclear positivity, sometimes posing significant difficulty in differentiating benign reticulum cells from single cell metastatic melanoma.

CONCLUSIONS

Our findings suggest that SOX-10 may be superior to S100 protein for identifying metastatic melanoma in a lymph node. KBA.62 was less sensitive than either marker, although more specific than S100 protein.

Update and Review on the Surgical Management of Primary Cutaneous Melanoma

The surgical management of malignant melanoma historically called for wide excision of skin and subcutaneous tissue for any given lesion, but has evolved to be rationally-based on pathological staging. Breslow and Clark independently described level and thickness as determinant in prognosis and margin of excision. The American Joint Committee of Cancer (AJCC) in 1988 combined features from each of these histologic classifications, generating a new system, which is continuously updated and improved. The National Comprehensive Cancer Network (NCCN) has also combined several large randomized prospective trials to generate current guidelines for melanoma excision as well. In this article, we reviewed: (1) Breslow and Clark classifications, AJCC and NCCN guidelines, the World Health Organization's 1988 study, and the Intergroup Melanoma Surgical Trial; (2) Experimental use of Mohs surgery for in situ melanoma; and (3) Surgical margins and utility and indications for sentinel lymph node biopsy (SLNB) and lymphadenectomy. Current guidelines for the surgical management of a primary melanoma of the skin is based on Breslow microstaging and call for cutaneous margins of resection of 0.5 cm for MIS, 1.0 cm for melanomas ≤1.0 mm thick, 1-2 cm for melanoma thickness of 1.01-2 mm, 2 cm margins for melanoma thickness of 2.01-4 mm, and 2 cm margins for melanomas >4 mm thick. Although the role of SLNB, CLND, and TLND continue to be studied, current recommendations include SLNB for Stage IB (includes T1b lesions ≤1.0 with the adverse features of ulceration or ≥1 mitoses/mm²) and Stage II melanomas. CLND is recommended when sentinel nodes contain metastatic deposits.