Seventh edition (2010) of gastric adenocarcinoma AJCC staging system: Is there room for improvement?

77 Background: The gastric cancer AJCC staging system recently underwent significant modifications of the T and N categories as well as stage groupings. The new system has not been validated on a US population database, but studies on Asian patients have reported no difference in survival between stages IB and IIA, as well as IIB and IIIA. Methods: California Cancer Registry data linked to Office of Statewide Health Planning and Development discharge abstracts were used to identify patients with gastric adenocarcinoma (gastroesophageal junction tumors excluded) who underwent curative-intent surgical resection from 2002 to 2006. AJCC stage was reclassified based on the 7th edition. Disease-specific survival (DSS) probabilities were calculated using the Kaplan-Meier method and compared using the log rank test. Results: Of 4,985 patients identified, 2,262 had complete pathologic data and known cause of death. Median age was 70 years and 60% were males. Median number of examined lymph nodes was 12 and 39% of patients received adjuvant chemotherapy. The 7th edition AJCC system did not distinguish outcome adequately between stages IB and IIA (P = .25), or IIB and IIIA (P = .33, Table ). By merging stage II into one category and moving T2N1 to stage IB and T2N2, T1N3 to stage IIIA, we propose a new grouping system which showed improved discriminatory ability ( Table ). Conclusions: In this first study validating the new 7th edition AJCC staging system for gastric cancer on a US population, we found stages IB and IIA, as well as IIB and IIIA to perform similarly. We propose a revised stage grouping for the AJCC system that better discriminates between outcomes. [Table: see text]