Population-based outcome of stage IA-IIA resected gastric adenocarcinoma: who should get adjuvant treatment?

Abstract

The benefit of adjuvant treatment in gastric adenocarcinoma was demonstrated by randomized, controlled trials of patients with locally advanced tumors. Thus, its role for stage IIB-IIIC disease is widely accepted. We aimed to identify patients with stage IA-IIA gastric adenocarcinoma who have a poor prognosis and thus may benefit from adjuvant treatment. Patients with gastric adenocarcinoma who underwent surgical resection with pathological evaluation of ≥15 lymph nodes and had available disease-specific survival (DSS) data were identified from the Surveillance Epidemiology and End Results Registry. Survival differences were evaluated with the log-rank test and Cox multivariate analysis. Stage and TN grouping strongly predicted DSS (P < 0.001, P < 0.001). Stage IA tumors had an excellent outcome: 91 ± 1.2 % 5-year DSS. The TN groupings of stages IB and IIA had the next best outcomes with 5-year DSS from 66 ± 4.6 % to 81 ± 2.3 %. Older age (P < 0.001), higher grade (P = 0.004), larger tumor size (P < 0.001), and proximal tumor location (P < 0.001) were independent predictors of worse DSS in stage IB-IIA tumors. We devised a risk stratification scheme for stage IB-IIA tumors where 1 point was assigned for age >60 years, tumor size >5 cm, proximal tumor location, and grade other than well-differentiated. Five-year DSS was 100 % for patients with 0 points; 86 ± 4.3 %, 1 point; 76 ± 3 %, 2 points; 72 ± 2.8 %, 3 points; and 48 ± 4.9 %, 4 points (P < 0.001). Patients with stage IB-IIA gastric adenocarcinoma and ≥2 adverse features (age >60 years, tumor size >5 cm, proximal location, and high-grade) have 5-year DSS ≤76 %. Adjuvant therapy may be warranted for these patients.