The Role of Lymphatic Mapping and Sentinel Lymph Node Biopsy in the Staging and Treatment of Melanoma

The incidence of malignant melanoma is increasing at an alarming rate, doubling in women and growing by more 300% in men during the past 25 years. The importance of diagnosing nodal metastatic disease, with the ability to detect smaller and smaller volumes of tumor in the sentinel lymph nodes (SLNs) biopsied using immunohistochemical staining, has impacted the accurate staging and stratification of melanoma patients. The role that elective lymph node dissection now plays in staging the melanoma patient and determining subsequent treatment has been greatly diminished in favor of less morbid and less invasive techniques that have a higher degree of accuracy in detecting occult nodal disease. This article explores what has driven the advent of selective or SLN biopsy, the rationale behind obtaining a preoperative lymphoscintigram, the technical details of the SLN biopsy procedure, and the refinement in the pathologic detection of ever smaller volumes of tumor in nymph node tissue removed. The role that these new modalities have played in changing the dynamic field of melanoma care is emphasized.