The prognosis of primary and metastasising melanoma. An evaluation of the TNM classification in 2,495 patients

Abstract

The prognostic value of the TNM classifications of the UICC dated 1978 and 1987, was investigated in a population of 2,495 patients who were followed up over the long term. In the case of primary melanoma, Breslow's tumour thickness proved to be the most powerful predictor of patient survival in multivariate analysis, while the significance of Clark's level ranged after that of both localisation of the primary tumour and the sex of the patient. The continuous proportional relationship between tumour thickness and risk of death makes it possible to regrade thickness groups. Grading cutoffs at 1, 2 and 4 millimetres, with no account being taken of depth of invasion, proved to be particularly favourable for a classification in accordance with prognostic criteria. In advanced stages of the disease, the outcome of locoregional and distant metastasis is significantly different; and furthermore in the case of locoregional metastasis, in-transit and satellite metastases exert a significantly better prognosis than regional lymph node involvement. Isolated juxtaregional lymph node metastases occurred primarily or during the course of the observation period in only 19 patients of our group, and, in comparison with visceral metastases, proved to have only an insignificantly better prognosis. For this reason, it would appear meaningful to assign them to a common stage. On the basis of these results, proposals are made for modifications of the TNM classification.