From 1949 to 1967, 176 cases of melanoma have been completely reviewed with a minimal follow-up period of six years including histologic reassessment, complete clinical evaluation, and current health or nature of death. With strict histologic criteria rather than clinical criteria, the incidence of lentigo maligna melanoma was 6 per cent; nodular melanoma, 20 per cent; and superficial spreading melanoma, 74 per cent. Compared with those of patients seen before 1949, the size and depth of invasion at diagnosis have improved greatly, and cure rate has more than doubled; current six year disease-free survival is 67 per cent. The current depth criteria of Clark are found to be unnecessarily complex and no more accurate in predicting survival than careful measurement of maximal diameter. Surgical therapy was conservative or radical primary resection and either observation or prophylactic resection or therapeutic resection for regional lymph nodes. No disadvantage in terms of cure or local recurrence was detectable using conservative local resections when reasonable criteria of local tissue sacrifice were observed. Several specific groups of patients could be defined by clinical and histologic criteria when there was potential benefit in prophylactic nodal resections. Thus, superficial spreading melanomas less than 1.5 cm in diameter or with level II depth of invasion or with 1+ mitotic rate constitute 50 per cent of all cases, yet they have less than a 10 per cent risk of nodal disease at any time in their clinical course whether cured or not. In contrast, with any melanoma of the leg and trunk, nodular melanoma in any location, or level V involvement in any clinical type, 30 per cent risk of regional nodal disease exists and prophylactic nodal resections are potentially useful. When prophylactic nodal resections are performed, conservative types of resections are the equivalent of radical resections and produce considerably less morbidity.
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