Prognostic index in malignant melanoma.

A retrospective study was undertaken of 146 surgically treated subjects with primary cutaneous melanoma of which 73 were disease-free for five to nine years and 73 developed later metastases. A prognostic factor was south to determine patients with poor prognoses. The best overall method was shown to be the evaluation of the prognostic index defined as the product of tumor thickness and the number of mitoses per square millimeter. However, for establishing a group of patients with no incidence of metastases, the mitotic rate proved to be as good a factor as the prognostic index and better than tumor thickness or levels of invasion. The application of this prognostic index seems therefore to be useful in selecting for further treatment stage I melanoma patients with poor prognoses, eg, prophylatic lymph node dissection and immunochemotherapy.