Malignant melanoma: correlation of long-term follow-up with clinical staging, level of invasion and thickness of the primary tumor.

: Sixty melanoma patients were followed 20 to 30 years after primary therapy, and survival rates were reviewed with reference to clinical and histological staging. All but one of the patients with clinically positive regional nodes died of metastatic disease. Two of nine patients with nonenlarged nodes that were clinically negative but histologically positive are alive 25 years after node dissections. Ten of 17 patients with negative nodes survived their operations by 20 to 30 years. Another series of 138 patients with stage 1 cutaneous melanoma were reviewed at the George Washington University Medical Center and tumor thickness was found to be a better measurement of prognosis than clinical or histologic staging, or the tumor's level of invasion. Prophylactic lymph node dissection appeared to double the survival of patients with lesions greater than 1.5 millimeters thick, but had no effect on those with thinner lesions. Thirty-nine per cent of the patients had lesions less than 0.76 mm thick, and all survived free of disease for five or more years. Of the tumors in the intermediate range of 0.76 to 1.50 mm thick, 33% metastasized or recurred; no clinical or pathologic discriminant could be detected that differentiated those patients who would have the recurring lesions from the others with tumors in this range of intermediate thickness who did well.