J. Datta1, M. T. McMillan1, L. Ruffolo1, R. Mamtani2, J. A. Drebin1, D. L. Fraker1, G. C. Karakousis1, R. Roses1 2University Of Pennsylvania,Medicine (Oncology),Philadelphia, PA, USA 1University Of Pennsylvania,Surgery,Philadelphia, PA, USA
Introduction: Multimodality therapy (MT) is a recommended component of treatment for early stage gastric adenocarcinoma (ESGA). Compliance with these guidelines, and the impact of MT on survival in ESGA has not been extensively explored. We examined (1) temporal trends in sequencing of MT, (2) factors associated with MT use, and (3) effect of MT receipt on overall survival (OS) in resected ESGA.
Methods: The National Cancer Data Base was queried for stage IB-II GA patients undergoing gastrectomy (1998-2011). Multivariate models were developed to identify factors associated with adjuvant chemoradiotherapy (ACRT) or perioperative chemotherapy (PC) receipt and to compare risk-adjusted OS by treatment group.
Results: Of 7,357 resected ESGA patients (median age 68 years, 69.1% male), 50.6%, 25.5%, and 23.9% received surgery only (SO), PC, and ACRT, respectively. Utilization of MT rose consistently between 1998 and 2011, increasing by 42.4% (p<0.001). While ACRT use increased only modestly (12.0%–23.5%, p=0.02), receipt of PC increased dramatically (8.0%–38.8%, p<0.001). Predictors of ACRT receipt were multifactorial, but most strongly associated with age<56 years (OR 3.31, 95% CI 2.62-4.17) and non-proximal tumor location (OR 2.78, 95% CI 2.42-3.19). Proximal tumor location (OR 3.79, 95% CI 3.26-4.41) and AJCC clinical stage IIB (OR 2.42, 95% CI 1.99-2.92) were the strongest predictors of PC use. Younger, white, higher-income, and less comorbid patients were also significantly more likely to receive PC (all p<0.01). Hospital-based selection of MT varied significantly by geographic region and academic affiliation (all p≤0.01). Survival analyses included 1,275 patients with a minimum follow-up of 5 years. Median, 1-yr, and 5-yr survival was 44.8 months, 75.0%, and 46.0% respectively. In this cohort, median survival was significantly longer for patients selected to receive MT (i.e. ACRT or PC) compared with those undergoing SO (47.1 vs. 43.3 months; p<0.001). R1 resection (HR 2.08, 95% CI 1.56-2.76), pathologic lymph node positivity (HR 1.91, 95% CI 1.65-2.22), and tumor T-classification 3/4 (HR 1.75, 95% CI 1.50-2.04) were strongly predictive of worse risk-adjusted OS. On stage-stratified Cox regression analysis, utilization of MT was independently associated with improved OS in both stage IB and II GA (IB: HR 0.65; p=0.002; II: HR 0.73; p=0.003).
Conclusion: Adoption of MT in ESGA is steadily increasing nationally, but remains incomplete. Patient-, tumor-, and hospital-related factors influence selection of MT sequence. In ESGA, MT receipt is independently associated with improved survival compared with undergoing SO.
