Correlation of Fitzpatrick Skin Type and Iris Color with Tumor Size in 823 patients with Uveal Melanoma

Abstract

Objective: To determine the correlation of Fitzpatrick Skin Type (FST) and iris color with tumor size (tumor thickness and basal diameter) in patients with uveal melanoma. Methods: Retrospective cohort from a single ocular oncology center of 823 patients with uveal melanoma and documented FST, iris color, and tumor size. Patients were classified into FST (type I, II, and III-V) and iris color (blue, green, and brown) on the basis of external facial photography. There were no FST type VI patients. Tumor thickness was classified into small [<3 millimeter (mm)], medium (3.1-8.0 mm), or large (>8.0 mm), and basal diameter into small (<10 mm), medium (10.1-15 mm) or large (>15mm). The correlation of FST and iris color with tumor thickness and basal diameter was evaluated using the Kruskal-Wallis H test. Results: The FST classification was type I (n=92, 11%), type II (n=643, 78%), or III-V (n=88, 11%), and iris color was blue (n=472, 57%), green (n=102, 12%), or brown (n=249, 30%). A comparison of FST revealed differences in mean tumor thickness (p= 0.04) and basal diameter (p=0.006). Iris color showed no difference for mean tumor thickness (p=0.41) or basal diameter (p=0.48). There was a difference with brown iris color relative to FST III-V for mean tumor thickness (p=0.003) and basal diameter (p=0.001) but no difference with blue or green iris color (p > 0.05). Conclusions: Iris color alone showed no difference in tumor size, but those with brown iris color and FST type III-V demonstrated larger tumor thickness and basal diameter.