A. A. Mokdad1, I. Nassour1, A. Ali1, J. C. Mansour1, A. C. Yopp1, R. M. Minter1, P. M. Polanco1, M. M. Augustine1, M. A. Choti1, S. C. Wang1, M. R. Porembka1 1University Of Texas Southwestern Medical Center,Surgery,Dallas, TX, USA
Introduction: Disparities in cancer care and survival are major obstacles to improved cancer outcomes in the United States. This study identified racial/ethnic differences in presentation, treatment, and survival among a national cohort of patients with gastric cancer.
Methods: Adults patients with gastric adenocarcinoma were identified in the National Cancer Data Base between 2006 and 2013. Patient demographics, tumor characteristics, treatment, and overall survival were compared among non-Hispanic whites (NHW), non-Hispanic blacks (NHB), Hispanics (HS), and Asians (AS). Racial/ethnic differences in stage-specific treatment were compared using a multivariable logistic regression model. A Cox proportional hazards model was used to compare risk-adjusted overall survival among race/ethnicity groups. The reference group was NHW unless otherwise noted.
Results: A total of 95,212 patients with gastric adenocarcinoma were identified; 63,511 (67%) patients were NHW, 14,764 (16%) NHB, 10,451 (11%) HS, and 6,486 (7%) AS. Compared to NHW, HS presented at an earlier age with 24% being diagnosed before the age of 50 (8% in NHW, p<0.01) and were more likely to have high grade tumors (grade 3 or 4: 74% vs 64%, p<0.01) and metastatic disease (33% vs 39%, p<0.01). Compared to NHW, AS were more likely to present with early stage disease (16% vs 11%, p<0.01). NHW were more likely to have cardia disease (49%), while NHB, HS, and AS presented most commonly with cancer of the antrum/pylorus (31%, 25%, and 34%, respectively). Overall, NHB were least likely and AS were most likely to receive any treatment (70% vs 78%, p<0.01). Among patients that underwent tumor resection, NHW were more likely to receive neoadjuvant therapy (21% vs 9% (NHB), 12% (HS), and 6%(AS), p<0.01) and less likely to receive adjuvant therapy (24% vs 37% (NHB), 37% (HS), and 37% (AS), p<0.01). On multivariable analysis, of the patients without metastatic disease, AS were more likely to undergo resection (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.27-1.53) while NHB were the least likely (OR, 0.80; 95% CI, 0.75-0.85). In addition, for patients with metastatic disease, NHB were the least likely to receive systemic chemotherapy (OR, 0.88; 95% CI, 0.82-0.95). AS, HS, NHW, and NHB had significantly different median overall survivals (24, 16, 13, and 12 months, respectively, log-rank p< 0.01). The survival advantage among AS and HS remained after adjusting for patient, tumor, and treatment factors (AS: hazard ratio [HR], 0.73; 95% CI, 0.70-0.76; HS: HR, 0.78;95% CI, 0.76-0.81).
Conclusion: Tumor presentation, treatment, and survival differ among racial/ethnic groups in gastric cancer. Notably, NHB are undertreated and HS have better survival despite more advanced disease. Racial/ethnic disparities in survival is not completely accounted for by tumor characteristics and treatment, and additional studies are need to determine the basis of these disparities.