S1620 Association of Insurance Status with Survival and Disease Stage at Presentation of Gastric Cancer: A National Cancer Database Analysis

Abstract

Introduction: In the US, 9.6% of the population (31 million people) do not have health insurance. Uninsured patients with cancer are more likely to present with advanced disease, not receive equal treatment, and display worse survival than those with insurance. Gastric cancer is one of the leading causes of death worldwide, and curative treatment depends on the disease stage at the time of diagnosis. The purpose of this study is to determine the association of insurance status with disease stage at presentation and survival among patients diagnosed with gastric cancer using the National Cancer Database (NCDB). Methods: The analysis cohort included gastric cancer patients in the NCDB diagnosed from 2010 to 2015. Patients were excluded if no information was available regarding insurance status or cancer staging at the time of diagnosis. Multivariable logistic regression models were used to determine the association between insurance status and gastric cancer stage at diagnosis/presentation. Cox regression models were used to determine the association between insurance status and all-cause mortality. Results: Following exclusions, 178,641 patients had gastric cancer during the study period. 171,199 patients (95.8%) had insurance in comparison to 7,442 patients (4.2%) who were uninsured. Univariate analysis between the groups demonstrated a statistically significant higher proportion of poor differentiation (53.2%), advanced disease (46.2%), and metastasis (41.9%) at diagnosis in the uninsured group (Table). After adjusting for demographic and socioeconomic variables, being insured was the main predictor for not having metastatic disease at diagnosis (OR = 0.60 [95% CI, 0.57-0.63]). Median time to all-cause mortality was estimated at 45 months for uninsured patients vs 60 months for insured patients (Figure). Conclusion: There is an association between insurance status and disease stage at time of diagnosis for patients with gastric cancer. Patients without insurance present with advanced disease and have a lower survival rate compared to insured patients. Lack of insurance compromises a person’s health because they are less likely to receive preventive care, are less able to afford prescription drugs, are more likely to be hospitalized for avoidable health problems, are more likely to be diagnosed in the late stages of disease, and once diagnosed tend to receive less therapeutic care.Figure 1.: a. Predictors of non-metastatic vs metastatic disease b. Kaplan-Meier Survival Estimates. Table 1. - Tumor Characteristics Insured (n= 171,199) Uninsured (n= 7,442) P-value Tumor size, mean (standard deviation), cm 4.42 +/- 4.6 5.50 +/- 4.7 < 0.001 Differentiation grade, No. (%) < 0.001 Well differentiated 12,244 (7.15) 384 (5.16) Moderately differentiated 36,394 (21.26) 1,230 (16.53) Poorly differentiated 78,541 (45.88) 3,960 (53.21) Undifferentiated, anaplastic 3,076 (1.80) 114 (1.53) Cell type not determined 40,944 (23.92) 1,754 (23.57) Tumor Stage at diagnosis, No. (%) < 0.001 Stage 0 3,081 (1.80) 40 (0.54) Stage I 35,769 (20.89) 852 (11.45) Stage II 21,970 (12.83) 723 (9.72) Stage III 27,921 (16.31) 1,159 (15.57) Stage IV 51,726 (30.21) 3,436 (46.17) Not applicable 5,066 (2.96) 205 (2.75) Unknown 25,666 (14.99) 1,027 (13.80) Metastatic disease, No. (%) < 0.001 No 115,122 (70.82) 3,815 (55.10) Yes 42,370 (26.07) 2,906 (41.97) Not Applicable 5,058 (3.11) 203 (2.93)