Socioeconomic Factors Associated With Thymoma Survival in the United States

Introduction: The effects of socioeconomic factors on patients diagnosed with thymomas have not been previously studied. We propose these factors have an important association with survival. Thymoma is the most common tumor of the anterior mediastinum. Compared to other neoplasms which can integrate different therapeutic approaches for treatment, the most effective therapy for local and locally advanced thymoma is complete surgical resection. This study aimed to elaborate on socioeconomic variables and their potential effects on the survival outcomes in patients diagnosed with thymoma.

Methods: Clinical data from the Surveillance, Epidemiology, and End Results 22 registry from 1975-2019 was used to define overall and cancer-specific survival of thymoma. The unadjusted analysis was followed by fitting a Cox proportional hazards model that included all variables assessed with Kaplan-Meier curves. An unadjusted Kaplan-Meier analysis was performed first comparing time to death by decade, age, race, ethnicity, sex, income, and region separately. The primary outcome was survival measured in months.

Results: We identified 1821 patients aged 18 y or over from the Surveillance, Epidemiology, and End Results database with a thymoma diagnosis between the years 1975 and 2019. The demographic variables considered were age, race, ethnicity (Hispanic/non-Hispanic), sex (male/female), inflation-adjusted income in 2019 dollars, and community size. We observed a decrease in mortality from thymic neoplasm across the decades. For each subsequent year, mortality risk decreased by 3.5% (P <0.001). The mortality risk of older patients was significantly higher. Compared to the youngest group, the mortality risk was 52.8% higher in the 50-year-old to 65-year-old category (P = 0.021). The mortality risk was 339% times higher in the 65 + age group (P <0.001). Income may be associated with risk reduction. Patients making greater than $75,000 had a 40.1% lower mortality risk than those making less than $50,000 (P = 0.029). The survival rate categorized by race was similar between Blacks and Whites but tended to be higher for the Asian and Pacific Islander groups without reaching statistical significance (P = 0.12).

Conclusions: Medical advancements have improved the overall thymoma survival in the past four decades. Yet, demographic, and socioeconomic factors such as age, income, and race may also play a role.