Lymph node metastasis in melanoma: a debate on the significance of nodal metastases, conditional survival analysis and clinical trials.

While there is no doubt that regional lymph node metastases are an enormously important factor in melanoma staging and treatment, the biology behind this significance and its precise implications for treatment planning have been a leading controversy in melanoma and other solid tumors for over a century. Recent clinical data, including data from prospective randomized clinical trials have refined our understanding of the process of nodal metastases and the advantages and disadvantages of different clinical management strategies. This review presents two points of view in this debate and discusses the results of new data analyses as well as pivotal clinical trials informing the discussion.