Real-world Treatment Patterns and Clinical Outcomes Across Lines of Therapy in Patients With Advanced/Metastatic Gastric or Gastroesophageal Junction Cancer

Background: First-line (1L) and second-line (2L) therapies for advanced/metastatic gastric cancer (GC) and gastroesophageal junction cancer (GEJC) have modest efficacy, and therapeutic options in subsequent lines are limited as disease progresses. We assessed real-world treatment patterns and outcomes for advanced/metastatic GC/GEJC. Patients and Methods: Adult patients diagnosed with advanced/metastatic GC/GEJC between January 1, 2011 and April 30, 2018 were identified using the Flatiron Health database. Median overall survival (OS) from start of each line of therapy until death was estimated by the Kaplan-Meier method. Duration of therapy (DoT) was time from start date until end date of each line. Results: We identified 3291 patients with advanced/metastatic GC/GEJC adenocarcinoma. At diagnosis, the median age was 68 years, 60% were white, 53% had initial stage IV disease, and 57% had GC. Of these 3291 patients, most (75%) received at least 1 therapy; 32% received 2L, 14% received third-line (3L) therapy, and 6% received at least 4 lines of therapy (4L+). The median OS from start of 1L was 10.7 months (2L, 7.6 months; 3L, 6.1 months; 4L+, 2.8 months). The median DoT in 1L was 2.2 months (2L, 2.1 months; 3L, 1.7 months; 4L+, 3.0 months). Use of targeted and immunotherapies generally increased progressively with each subsequent line of therapy. Conclusion: One-quarter of patients with advanced/metastatic GC/GEJC remained untreated, and only approximately one-half of patients receiving 1L therapy received subsequent treatment. In all lines of therapy, OS was generally poor and DoT was short. More effective treatment options are needed across all lines of therapy for this highly burdensome disease.