S1369 Gastric Cancer Survival and Associations in the Rural Developing Nation Setting in Central America

Abstract

INTRODUCTION: Two-thirds of global cancer will occur in low/middle income countries (LMICs), dominated by the seven major cancers, including gastric cancer. The Central America Four region (CA-4), with a population of 36M and >5M immigrants in the U.S., is the largest LMIC region in the western hemisphere, and primarily rural.[1] We conducted a gastric cancer survival study in rural western Honduras, characterized as having among the highest incidence rates in Latin America.[2] METHODS: In an ongoing population-based gastric cancer case-control study, we identified incident cases of gastric adenocarcinoma (2002–15).[3] Active follow-up to rural/remote households was performed. Relative socioeconomic status was quantified with the U.N. unsatisfied basic needs index (UBN). Pyloric obstruction (incomplete, complete) was used as a proxy for staging. Data collection used REDCap. Cox regression models were designed with STATA14. RESULTS: Survival follow-up was achieved in a total of 591/617 (95.8%), meeting international completeness criteria. The median age at diagnosis was 64 years (IQR 55–73), and 24.5% were age <55. Two-thirds were male (402, 65.2%). One-third of households (35.5%) were impoverished (UBN 2–4). 22% and 17% of tumors had complete and incomplete pyloric obstruction, respectively. Few patients presented with early gastric cancer. 44%, 44%, and 8% of histology was intestinal, diffuse, and mixed, respectively. 16.6% patients received treatment, primarily palliative or curative surgery, and few patients (5.6%) received chemotherapy; treatment status was unknown in 32.9%. Male and female 5-year survival rates were 10.3% and 11.8%, and 1-year rates were 30.8% and 33.1%, respectively. The 5-year survival rate for patients age <45 was 7.7%. The mean survival time was 3.8 (95% CI, 3.4–4.4) months. In the final Cox regression model including age, sex, Lauren subtype, and poverty index, only treatment was significantly associated with survival (HR 0.40, 0.31–0.51). CONCLUSION: Markedly low gastric cancer 5-year survival rates are observed in the rural LMIC setting in Central America, consistent with the CONCORD-3 results,[4] and with implications for U.S. immigrants. The majority of patients present with advanced disease and few have access to therapy. Coordinated cancer diagnosis and care programs have the potential for significant improvements in cancer control.