Incidence, clinical features, and survival outcomes of primary malignant conjunctival tumor: a US population-based retrospective cohort analysis based on the SEER database (1975-2018)

Transl Cancer Res. 2025 Mar 30;14(3):1609-1625. doi: 10.21037/tcr-24-1629. Epub 2025 Mar 27.

ABSTRACT

BACKGROUND: Primary malignant conjunctival tumors (PMCT) are rare. Their clinicopathological characteristics and survival outcomes are not well understood. The Surveillance, Epidemiology, and End Results (SEER) database includes approximately 30% of the total US. In this study, we aimed to investigate the epidemiology, clinical characteristics, and prognosis of PMCT via SEER.

METHODS: Data on microscopically confirmed PMCT patients from 1975 to 2018 were retrieved. Patients who were lost to active follow-up, those for whom PMCT was not the primary malignant tumor, and those with unknown death information, laterality, race, or those who survived for less than 1 month after diagnosis were excluded. Disease-specific survival (DSS) and overall survival (OS) were the primary endpoints, calculated through the Kaplan-Meier analysis and log-rank tests. Univariate and multivariate Cox regression analyses were conducted to recognize independent predictive factors for DSS and OS.

RESULTS: In total, we identified 2,853 eligible patients diagnosed with PMCT, with an average age of 61.25 years, among which 1,678 (58.82%) were males, 2,464 (86.37%) were whites, 1,567 (54.92%) were married, and 2,125 (74.48%) were in localized SEER stage. The three major types were lymphoma (39.64%), squamous cell carcinoma (SCC) (34.88%), and melanoma (21.98%). The overall incidence of PMCT was 0.136/100,000 between 1975 and 2020, with an annual incidence rate of 0.929 [95% confidence interval (CI): 0.289-1.573, P<0.05]. Multivariate Cox regression analysis discovered age, sex, marital status, histological type, SEER stage, and surgery as independent prognostic variables. Age ≥75 years [≥75 vs. <60 years, hazard ratio (HR) =3.211, 95% CI: 2.309-4.466, P<0.001], melanoma (melanoma vs. SCC, HR =4.637, 95% CI: 3.235-6.649, P<0.001), distant SEER stage (distant vs. localized, HR =4.318, 95% CI: 2.675-6.968, P<0.001), and no/unknown surgery status (performed vs. no/unknown, HR =1.565, 95% CI: 1.187-2.062, P=0.001) were related to worse DSS. Meanwhile, age ≥75 years (≥75 vs. <60 years, HR =9.399, 95% CI: 7.876-11.216, P<0.001), male (female vs. male, HR =0.701, 95% CI: 0.612-0.803, P<0.001), unmarried status (unmarried vs. married, HR =1.342, 95% CI: 1.17-1.538, P<0.001), distant SEER stage (distant vs. localized, HR =2.077, 95% CI: 1.498-2.881, P<0.001), and no/unknown surgery status (performed vs. no/unknown, HR =1.16, 95% CI: 1.018-1.322, P=0.03) were related to worse OS. Lymphoma (lymphoma vs. SCC, HR =0.628, 95% CI: 0.533-0.74, P<0.001) was associated with better OS.

CONCLUSIONS: PMCT incidence increased after 1975 and decreased after 1997. Age, histological type, SEER stage, and surgery were all significantly associated with DSS and OS. Age ≥75 years, melanoma, and distant SEER stage were associated with worse DSS, while age ≥75 years, male, unmarried status, distant SEER stage were related to worse OS and lymphoma was related to better OS. Surgery may improve the prognosis of patient with PMCT.

PMID:40225001 | PMC:PMC11985212 | DOI:10.21037/tcr-24-1629