Predictors of heterogeneity in the first-line treatment of patients with advanced/metastatic gastric cancer in the U.S

Background: Patients with metastatic gastric cancer have a poor prognosis (5-year survival of less than 10%). This study was designed to describe the treatment patterns of patients with gastric cancer and to understand the factors associated with treatment choices to inform evidence-based care.

Methods: A retrospective observational study was conducted using two real-world databases to describe treatment trends and to quantify variability in treatment patterns of patients diagnosed with advanced/metastatic gastric cancer between 1/1/2007 and 9/30/2014 in the U.S. Heterogeneity was measured by the Herfindahl-Hirschman Index (HHI). Predictors (baseline clinical, treatment, and demographic variables) of treatment regimen choice were evaluated using logistic regression.

Results: A total of 5772 patients with advanced/metastatic gastric cancer were included in this study [5044 from claims data and 728 from electronic medical records (EMR)]. Of the 5044 from claims data, 2457 had evidence of metastatic disease at diagnosis. Only the fluorouracil + oxaliplatin regimen exceeded 10% utilization in the first-line setting [claims metastatic (12.1%), claims advanced (8.2%), and EMR metastatic (16.6%) cohorts]. The HHI demonstrated extreme heterogeneity (0.14 for first-line therapy and 0.13 for second-line therapy). Patient age and geographic region of residence were significantly associated with treatment choice across all three cohorts in the first-line setting (p < 0.05).

Conclusion: Treatment of patients with gastric cancer was highly variable. Despite the availability of treatment guidelines, there is a lack of consistent treatment patterns. There is a need to improve evidence-based care for patients with gastric cancer.