Purpose: The aim of this study was to evaluate conjunctival melanoma outcomes based on American Joint Committee on Cancer classification. The study design constituted a nonrandomized interventional case series.
Methods: This was a retrospective chart review comprising 343 participants, and the main outcome measures were melanoma local recurrence, lymph node metastasis, distant metastasis, and death.
Results: On the basis of the American Joint Committee on Cancer classification (seventh edition), conjunctival melanoma was classified as T1 (196 [57%]), T2 (110 [32%]), T3 (37 [11%]), and T4 (0). The mean tumor basal diameter increased with tumor staging with 8.5 mm for T1, 12.7 mm for T2 (p = 0.0003), and 16 mm for T3 (p < 0.0001). The melanoma arose from primary acquired melanosis (T1 = 71%; T2 = 84%; T3 = 81%), preexisting nevus (T1 = 8%; T2 = 5%; T3 = 3%), or de novo (T1 = 21%; T2 = 12%; T3 = 16%). Outcomes at 5 years (Kaplan-Meier) revealed melanoma local recurrence/new tumor in 44% T1, 78% T2 (p < 0.0001), and 76% T3 (P=0.0044); regional lymph node metastasis in 17% T1, 52% T2 (p < 0.0001), and 49% T3 (p = 0.0092); melanoma-related distant metastasis in 11% T1, 35% T2 (p < 0.0001), and 42% T3 (p = 0.0018); and melanoma-related death in 5% T1, 20% T2 (p = 0.0655), and 23% T3 (p = 0.0526). Based on American Joint Committee on Cancer classification, factors predictive of melanoma recurrence included T2 stage (p < 0.0001), and T3 stage (p = 0.0061). After adjusting for tumor origin, factors predictive of regional lymph node metastasis, melanoma-related distant metastasis, and melanoma-related death included melanoma arising de novo (p < 0.0001; p < 0.0001; p < 0.0001), T2 stage (p < 0.0001; p < 0.0001; p = 0.007), and T3 stage (p = 0.005; p = 0.0014; p = 0.0342).
Conclusion: The American Joint Committee on Cancer staging predicts prognosis of conjunctival melanoma. Melanoma classified as T2 and T3 (compared with T1) showed significantly higher rates of local recurrence, regional lymph node metastasis, distant metastasis, and death.