A nationwide population-based study comparing survival in unresectable advanced or synchronous metastatic esophageal and gastric adenocarcinoma.

Abstract

308 Background: Similarities between esophageal and gastric adenocarcinomas have been identified in terms of genomic characteristics. There is however no consensus on the combined or stratified inclusion of esophageal adenocarcinoma (EAC) within gastric cancer (GC) clinical trials. The aim of our study was to compare patient and tumor characteristics, first-line treatment regimens and overall survival (OS) of patients with EAC and GC. Methods: We selected patients with unresectable advanced and/or synchronous metastatic EAC (n = 1554) or GC (including junction tumors; n = 2095) diagnosed in the period 2015-2017 from the nationwide Netherlands Cancer Registry. Patients with a positive HER2 test result and/or receiving trastuzumab as a first-line treatment were excluded. Data on OS were analyzed using Kaplan-Meier curves with Log-Rank test. Results: The EAC patient population had significantly more male patients (83% vs 66%), lower median age (68 vs 71 years) and higher median BMI (25.4 vs 24.5). Significant differences in location of metastases were identified, with higher percentages in non-regional lymph nodes (48% vs 28%), liver (50% vs 35%), lung (21% vs 9%) and bone (19% vs 7%) and lower in peritoneum (5% vs 42%), in EAC versus GC patients respectively. EAC patients more often received any type (supportive or active systemic) of treatment (76% vs 60%). Median OS was longer in EAC than GC patients (EAC: 4.8 vs GC: 4.1 months; p < 0.01). The percentages of patients receiving first-line systemic treatment were equal in both groups (43%). The number of patients receiving CapOx or FOLFOX was not significantly different (43% vs 47%). Carboplatin+paclitaxel was more frequently given in EAC versus GC (34% vs 3%), while EOX or ECC was given less frequently (12% vs 30%). No significant difference was observed in median OS between EAC and GC patients receiving first-line active systemic treatment (8.0 vs 7.6 months; p = 0.28). Conclusions: Patient characteristics, tumor characteristics, treatment regimens and OS differ between EAC and GC patients. Despite these differences, in patients receiving first-line active systemic treatment no significant differences in OS were found.