Proliferation rates in human malignant melanoma: relationship to clinicopathological features and outcome

This prospective study investigated the clinical significance of cell kinetics, measured using bromodeoxyuridine injection and flow cytometry, in primary and metastatic cutaneous malignant melanoma. The findings illustrate that melanoma is a relatively slowly proliferating tumour, with a median potential doubling time (T(pot)) of 8.6 days. There were no significant differences in cell kinetics between primary and secondary disease. Both the duration of the S phase (T(s)) and T(pot), but not the labelling index (LI), showed a correlation with some of the main clinicopathological features in primary disease, including Breslow thickness. On univariate analysis, a short T(pot) and a high LI were associated with shorter disease-free intervals and overall survival for metastatic but not primary lesions. On multivariate analysis, these parameters retained significance when analysed separately with the main clinicopathological variables. These findings suggest that assessment of proliferation in melanoma is able to refine the available prognostic information and identify patients with a poor clinical outcome.