Do Largest Basal Tumor Diameter and the American Joint Committee on Cancer's Cancer Staging Influence Prognostication by Gene Expression Profiling in Choroidal Melanoma

Abstract

To evaluate the prognostication of choroidal melanoma (CM) by the gene expression profiling (GEP) test. Cohort study. Retrospective review of 293 CM patients from 2 centers. Of 293 patients, 132 (45%) were class 1A by GEP, 63 (22%) were class 1B, and 98 (33%) were class 2. Class 2 tumors had more ciliary body involvement and greater largest basal dimension (LBD), and were thicker. GEP results and increasing LBD were independently predictive of time to metastasis. Kaplan-Meier survival analysis estimated the probability of 3-year metastasis-free survival (MFS) of 0.99 in class 1A, 0.90 in class 1B, and 0.60 in class 2. The probability of 3-year MFS was 0.49 in class 2 patients with LBD ≥ 12mm vs 1.00 in those with LBD < 12mm, 0.89 in class 1B with LBD ≥ 12mm vs 0.93 in those with LBD < 12mm, and 0.99 in class 1A with LBD ≥ 12mm vs 1.00 in those with LBD < 12mm. In American Joint Committee on Cancer (AJCC) stage I CMs, the probability of 3-year MFS was 1.0 for class 1A and 1B, and 0.79 for class 2. In stage II CMs, the probability of 3-year MFS was 0.99 for class 1A, 0.89 for class 1B, and 0.61 for class 2. In stage III CM, the probability of 3-year MFS was 1.0 for class 1A, 0.60 for class 1B, and 0.41 for class2. GEP testing provided significant prognostic information for CM. Class 2 tumors with LBD ≥ 12mm and class 2 and 1B tumors with AJCC stage III showed significantly worse prognosis.