Microstages in malignant melanoma--the basis for an elective lymph node dissection.

Our experience has shown that an increasing depth of invasion of the primary tumor is connected with a higher incidence of regional lymph node metastases. The incidence of subsequent metastases or recurrences is compared retrospectively for two groups: (1) 175 patients with elective dissection and (2) 33 patients with excision only. All patients suffered from high-risk melanomas of clinical stage I. The frequency of subsequent metastases was 21% (N = 36) for the first group and 46% (N = 15) for the second group (p less than or equal to 0.01). The 5-year survival rate (Berkson-Gage) of patients with high-risk melanomas and secondaries is 41% for the patient group (N = 27) in which elective dissection was performed and 21% for patients with therapeutic dissection (N = 52). The results speak for the elective dissection in cases of high-risk melanomas.