Thickness, cross-sectional areas and depth of invasion in the prognosis of cutaneous melanoma.

TLDR: The depth of invasion was studied using the criteria for staging of Clark et al.2 to see if maximal cross-sectional area, thickness, stage of invasion, or a combination of these can be of value in assessing the prognosis of cutaneous melanoma.

Abstract: CuTANEous melanoma is a most unpredictable lesion. The marked variation in prognosis is probably a function of many variables, one of which is the size of the tumor. Though there is a roughly inverse relationship between the diameter of the lesion and survival,5 very small lesions have recurred or metastasized. One possible reason for the lack of reliability of tumor size in estimating prognosis may be that studies to date have considered size in only two diamensions and have neglected tumor volume. Two melanomas can have the same diameter but differ greatly in thickness because of variation in either depth of invasion or degree of protrusion from the surface of the skin or both. A recent study 2 has shown that prognosis correlates well with staging of the depth of invasion, but there have been no studies relating survival to tumor volume. To measure tumor volume it is necessary to know the surface area of the tumor, but in this retrospective study we only know the maximal diameters of the lesions. By measuring the maximal thickness of the lesions we can calculate the maximal crosssectional area, which should be roughly proportional to the volume of the tumor. The depth of invasion was also studied using the criteria for staging of Clark et al.2 to see if maximal cross-sectional area, thickness, stage of invasion, or a combination of these can be of value in assessing the prognosis of cutaneous melanoma. A total of 98 lesions were so studied.