Metastatic gastric cancer: Does the site of metastasis make a difference?

Abstract

Background: Metastatic gastric cancer has a poor prognosis. We aim to study how clinical features and prognosis differs between different metastatic sites, and to identify prognostic factors for overall survival.

Methods: We retrospectively reviewed patients with metastatic gastric adenocarcinoma managed at a tertiary referral cancer center over a 5-year period. We divided our cohort into three groups based on the site(s) of metastasis at presentation-peritoneal metastasis only (P), distant metastasis only (D), and peritoneal and distant metastases (PD).

Results: We studied 470 patients with 175 (37.2%), 193 (41.1%) and 102 (21.7%) patients in the P, D and PD groups, respectively. Patients with peritoneal disease (both P and PD) had higher proportions of patients experiencing chemotherapy disruption due to unplanned hospitalizations, which were also of a longer average duration. The P group had the longest overall median survival of 8.9 months compared to the PD and D groups with 7.4 and 5.5 months, respectively (P < 0.001). On multivariate Cox regression analysis, the presence of ≥1 metastatic site (hazard ratio [HR] 1.67; 95% confidence interval [CI], 1.23-2.28; P = 0.001) was significantly associated with increased overall mortality, whereas palliative systemic chemotherapy (HR 0.29; 95% CI, 0.22-0.37; P < 0.001) and palliative gastrectomy (HR 0.24; 95% CI, 0.15-0.39; P < 0.001) were significantly associated with decreased overall mortality.

Conclusion: Metastatic gastric cancer represents a heterogeneous disease, with specific disease complications and treatment outcomes unique to different metastatic sites. We can consider novel multimodality therapies for patient subgroups with isolated metastatic disease and good prognostic factors in a bid to improve long-term survival.

Keywords: metastatic gastric cancer; metastatic site; prognostic factors.