Prognostic factors and survival for malignant conjunctival melanoma and squamous cell carcinoma over four decades.

Abstract

To determine the epidemiology and survival of primary conjunctival malignant neoplasms. Retrospective analysis of primary malignant conjunctival neoplasms using Surveillance, Epidemiology, and End Results database from 1973 to 2012. Of 1661 cases, the most common neoplasms are squamous cell carcinoma (SCC) at 54.8% and melanoma at 38.8%. Mean diagnostic age for melanoma was 62.1 compared to 65.5 years for SCC (p = 0.002). 52.2% of melanoma are male versus 77.4% of SCC (p < 0.001). For SCC only age (HR: 1.09, 95% CI:1.04-1.14) is a predictor of survival. For melanoma, age (HR: 1.07, 95% CI: 1.05-1.10), male sex (HR: 2.04, 95% CI: 1.16-3.60), T4 tumors (HR: 3.38, 95% CI: 1.17-9.80) and N1 status (HR: 8.69, 95% CI: 2.75-27.42) are all survival predictors. The 5 and 10-year overall survival (OS) estimates are not significantly different between SCC and melanoma, with 70% and 50% respectively for SCC, and 71% and 50% respectively for melanoma. Median survival time is worse for blacks (52 months) compared to whites (118 months) and Asians/Native Americans/Pacific Islanders (145 months), however race was not found to be a significant prognostic factor in multivariate analysis. Five-year survival are similar between decades 1973-1982 (66.2%), 1983-1992 (69.2%), 1993-2002 (71.3%) and 2003-2012 (70.2%). Age at diagnosis is a determinant of survival for both conjunctival SCC and melanoma. Male sex, T4 and N1 staging are also important prognostic factors for melanoma. With respect to overall survival, SCC and melanoma did not differ significantly.