Track: Clinical Studies

Topic: Melanocytic Neoplasms

Abstract:

McGovern (1970) showed that melanoma nuclear grade significantly correlated with survival, and nuclear grade is used in various cancers other than melanoma. We sought to reproduce McGovern’s nuclear grade as a histologic indicator of melanoma prognosis. This is a retrospective analysis of 544 melanomas from 2020-2023 with median follow-up time of 411 days; 89 patients progressed, and 22 died of disease. A dermatopathologist assigned nuclear grade by microscopic evaluation of nuclear size, membrane contour, character of nucleoli, and chromatin arrangement. Grade 1 resembles nevus nuclei, Grade 3 shows extremes of nuclear abnormalities, and Grade 2 represents abnormalities between Grades 1 and 3. Kaplan-Meier survival curves were utilized to determine progression-free survival based on nuclear grade, which demonstrated a significant difference between Grade 3 and Grades 1 and 2 (p<0.003). Statistical analyses were conducted in R, using Student’s T-test, Chi-sq, or Kruskal Wallis tests. Grade 3 vs. Grade 1 lesions had older mean age and increased Breslow thickness, mitoses, ulceration, overall stage, and death from disease (each p<0.05). In a univariate Cox proportional hazard model, Grade 2 (HR: 1.7; 95% CI: 0.7-4.0) and Grade 3 (HR: 3.6; 95% CI: 1.5-8.4) lesions were associated with increased probability of progression vs. Grade 1 lesions. Adjusting the covariates noted above attenuated the hazard ratios for nuclear grades 2 and 3 to 1.2 (95% CI: 0.5-2.9) and 1.7 (95% CI: 0.7-4.2), respectively. Studies with longer follow-up and more outcomes are needed to assess nuclear atypia as an independent predictor of melanoma progression or mortality.

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David Ollila, MD