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

ABSTRACT

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.