Clinical evidence for three distinct gastric cancer subtypes: time for a new approach.

BACKGROUND: Recently, a new classification for gastric cancer (GC) has been proposed, based on Lauren's histology and on anatomic tumour location, identifying three subtypes of disease: type 1 (proximal non diffuse GC), type 2 (diffuse GC) and type 3 (distal non diffuse GC). Aim of our analysis was to compare clinical outcome according to different GC subtypes (1,2,3) in metastatic GC patients receiving first-line chemotherapy. PATIENTS AND METHODS: Advanced GC pts treated with a first-line combination chemotherapy were included in our analysis. Pts were divided in three subgroups (type 1, type 2 and type 3) as previously defined. RESULTS: A total of 248 advanced GC pts were included: 45.2% belonged to type 2, 43.6% to type 3 and 11.2% to type 1. Patients received a fluoropyrimidine-based chemotherapy doublet or three drugs regimens including a platinum derivate and a fluoropyrimidine with the addition of an anthracycline, a taxane or mytomicin C. RR was higher in type 1 pts (RR = 46.1%) and type 3 (34,3%) compared to type 2 (20,4%), (p = 0.015). Type 2 presented a shorter PFS, median PFS = 4.2 months, compared to type 1, mPFS = 7.2 months, and type 3, mPFS = 5.9 months (p = 0.011) and also a shorter OS (p = 0.022). CONCLUSIONS: Our analysis suggests that GC subtypes may be important predictors of benefit from chemotherapy in advanced GC patients. Future clinical trials should take in account these differences for a better stratification of patients.