Elective lymph node dissection for malignant melanoma: the tumor burden of nodal disease.

Many retrospective trials have demonstrated a survival benefit for elective lymph node dissection (ELND) in the treatment of clinical stage I malignant melanoma, but two randomized trials have found none. The relevant medical literature was reviewed with special attention devoted to the tumor burden of nodal disease. Following the lead of Handley, the biologic behavior of melanoma is compared to that of breast cancer. Patient survival appears to be determined by the volume of tumor cells circulating from the primary lesion or the regional nodes. A hypothesis is presented which suggests that metastatic disease develops only in those patients whose circulating tumor burden exceeds the host defense threshold of the patient--a threshold that is relatively stable throughout life. Some studies may have exaggerated the potential benefit of ELND, because some patients treated with delayed dissection were not closely followed and developed sizable nodal recurrence. Patients who decline ELND must be followed every one to three months. Investigators should precisely measure and report the volume of each patient's nodal disease. The debate over ELND can only be resolved with accurate data which begin to define the threshold at which nodal disease contributes to patient mortality.