(ChemotherapyAdvisor) – Gastric cancer subtypes may be important predictors of patient outcome and response to treatment with bevacizumab, an exploratory analysis of 733 of 744 patients in the global phase 3 AVAGAST trial has found. In all regions, regardless of treatment, those with diffuse gastric cancer (type 2) had worse outcome than distal non-diffuse disease (type 3); median overall survival was 10.3 vs. 11.7 months (HR=0.82; 95% CI, 0.68–1.00), investigators reported during the ASCO 2012 Gastrointestinal Cancers Symposium.

Currently, gastric cancer subtypes are treated as a single disease. In the AVAGAST study, patients in the Americas and Europe showed more benefit of treatment with first-line capecitabine and cisplatin with or without bevacizumab than Asia-Pacific patients, Manish A. Shah, MD, of Memorial Sloan-Kettering Cancer Center, New York, NY, and colleagues reported. Type 2 gastric cancer (52.1%) was more common than proximal non-diffuse type 1 (9.5%) or type 3 (38.3%) in this study.

The poorest prognoses were observed in American and European patients, 8.0 vs. 11.1 months (HR=0.68; 95% CI, 0.53–0.89). However, these individuals were most likely to benefit most from treatment with bevacizumab vs. placebo: median OS for type 2 gastric cancer was 9.9 vs. 6.5 months (HR=0.68; 95% CI, 0.48–0.97) and type 3 median OS was 11.7 vs 9.0 months (HR=0.72; 95% CI, 0.48–1.07). In those with type 1 gastric cancer, median OS was 10.4 months for the bevacizumab arm vs. 12.8 months for placebo (HR=1.50; 95% CI, 0.77–2.93).

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The investigators concluded that further prospective evaluation of gastric cancer subtypes is warranted.

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