The following is a summary of “Improved Staging of Ciliary Body and Choroidal Melanomas Based on Estimation of Tumor Volume and Competing Risk Analyses,” published in the October 2023 issue of Ophthalmology by Stålhammar et al.
The current American Joint Committee on Cancer (AJCC) 8th Edition staging model for uveal melanoma does not adequately differentiate survival outcomes for patients in advanced stages and may misclassify tumors based on size alone.
Researchers performed a retrospective study to develop a new model for predicting metastatic death in uveal melanoma patients based on tumor volume estimates.
They treated 6,528 consecutively registered patients at three tertiary ocular oncology centers on two continents (1981 and 2022). Data on all 6,528 patients’ survival, tumor size, and extent were collected. Tumor volume was calculated with a simple equation using the largest basal diameter and thickness. Size categories and stages based on volume were developed and validated in distinct patient groups through competing risk analyses, exploring associations with cytogenetic and cytomorphological features.
The results showed 6,528 patients categorized into 7 stages (V-stages IA, IB, IIA, IIB, IIIA, IIIB, and IIIC) based on estimated tumor volume and anatomic extent, with a 15-year incidence of metastatic death ranging from 7% to 77%. A new category, V1min, and corresponding stage IA were introduced, indicating an excellent prognosis. Metastatic mortality in V-stage IIIC significantly surpassed that in V-stage IIIB (P=0.03), while incidence curves intersected for patients in AJCC stage IIIC vs. IIIB (P=0.53). Uni- and multivariate competing risk regressions revealed higher Wald statistics for V-stages than AJCC stages (1152 vs. 1038 and 71 vs. 17, respectively). The frequencies of monosomy 3, a gain of chromosome 8q, and epithelioid cytomorphology increased with tumor volume (R2 0.70, 0.50, and 0.71, respectively, P<0.001) and exhibited similar correlations with AJCC and V-stages.
They concluded that estimating tumor volume can improve the accuracy of staging and prognostication for the ciliary body and choroidal melanomas.