Stereological quantification of tumor volume, mean nuclear volume and total number of melanoma cells correlated with morbidity and mortality

Stereological quantification of tumor volume, total number of tumor cells and mean nuclear volume provides unbiased data, regardless of the three-dimensional shape of the melanocytic lesion. The aim of the present study was to investigate whether these variables are reproducible and may represent potential indicators of prognosis. Sixty patients who underwent surgery at the Department of Plastic Surgery, Aarhus University Hospital, from 1991 to 1994 were included in the study. Total tumor volume was estimated by the Cavalieri technique, total number of tumor cells by the optical dissector principle, and nuclear mean volume by point counting. Tumor volume, total number of tumor cells and nuclear mean volume were all reproducible parameters, showing a non-significant intra-observer variation (p=0.72; p=0.83, and p=0.15). Grouped according to the median values, the disease-free survival time was significantly different for tumor volume as well as total number of tumor cells (p=0.0006 and p=0.0004), but no significant difference in mortality was found (p=0.1 and p=0.06). The mean nuclear volume showed no difference regarding disease-free survival or mortality (p=0.5 and p=0.8). Breslow's thickness showed a significant impact on both disease-free survival (p=0.001) and mortality (p=0.009). In conclusion, tumor volume and total number of cancer cells were highly reproducible but did not add additional, independent prognostic information regarding the study population.