Thickness and diameter in melanoma: is there a relation?

Objective: To evaluate the relationship between diameter and Breslow's thickness in skin melanoma. Methods: 2,071 skin melanomas incident in the area of activity of the Tuscany Cancer Registry (central Italy) were analyzed. Pearson's linear correlation coefficient r was computed between diameter and Breslow's thickness. Results: There was a statistically significant, but rather small, correlation between diameter and Breslow (r = 0.39). The same was true for men and women, for older and younger patients, and for skin subsites. 22.3% of the examined skin melanomas had a diameter <= 6 mm. Conclusions: There was a statistically significant, but small, correlation between Breslow's thickness and diameter in skin melanomas. Moreover, a non-negligible proportion of small lesions were thick and/or nodular.