Abstract
BACKGROUND: The Japan Clinical Oncology Group (JCOG) prognostic index, consisting of performance status, primary tumor resected, number of metastases, and serum alkaline phosphatase, has been one of the robust prognostic indices for patients with advanced gastric cancer on the basis of which clinical trials have stratified prognosis. Only a few studies, however, have utilized the JCOG prognostic index in daily practice. METHODS: We conducted a retrospective study on patients with advanced gastric cancer who received first-line platinum-containing chemotherapy at a single institute between 2011 and 2017. Prognostic factors were evaluated using a Cox proportional regression model. RESULTS: A total of 608 patients were enrolled. Multivariate analysis showed that performance status ≥1, presence or absence of primary tumor, serum alkaline phosphatase, neutrophil-to-lymphocyte ratio ≥4, and diffuse-type histology were significantly associated with worse prognosis, whereas the number of metastases was not. Although the original prognostic index could not adequately stratify patients into three risk groups, the modified index (good: 0 and 1, moderate: 2 and 3, poor: 4-6), which was established by incorporating diffuse-type histology and high neutrophil-to-lymphocyte ratio, demonstrated excellent stratification. The median overall survival of the good (n = 315), moderate (n = 243), and poor (n = 54) risk groups was 20.5, 13.5, and 10.2 months, respectively. Hazard ratios (HRs) were 1.69 [95% confidence interval (CI), 1.40-2.04; good versus moderate] and 1.52 (95% CI, 1.11-2.08; moderate versus poor). This novel index also demonstrated a statistically significant stratification of survival after progression following first-line chemotherapy (good versus moderate: HR, 1.41; 95% CI, 1.16-1.70; moderate versus poor: HR, 2.00; 95% CI, 1.45-2.74). CONCLUSIONS: The modified JCOG prognostic index showed excellent stratification of overall survival in real-world patients, which could also help determine the need for treatment changes throughout the continuum of chemotherapy.