Adjuvant therapy of gastric cancer: have we made any progress?

Up to now, the majority of adjuvant chemotherapy trials in gastric cancer have failed to show a clear survival benefit as compared to surgical controls, and this is especially true for trials conducted in western countries. But this does not necessarily mean, that adjuvant chemotherapy of gastric cancer is in general ineffective. There are several common threads that appear repeatedly in adjuvant therapy trials which might help to explain the current situation. In most trials stratification was done according to stage and not to the TNM category leading to important stratification bias. A homogeneous surgical approach and a surgical and pathological quality control was not mandatory. There are sufficient data, that in comparison to 'limited' surgery, extended surgery with systematic lymphadenectomy of the N2 compartment markedly improves the prognosis of patients with stage II and IIIa tumors. The kind of chemotherapy, its timing and scheduling, and route of administration might also have been inappropriate to demonstrate a possible benefit of adjuvant therapy. All these things have to be considered seriously in future well designed trials, if an assumed therapeutic gain is to be demonstrated by adjuvant treatment of gastric cancer.