Nishina T, et al. - Researchers analyzed data from the G-SOX study comparing S-1 plus oxaliplatin with S-1 plus cisplatin as the first-line treatment for advanced gastric cancer (AGC) to investigate early tumor shrinkage (ETS) and depth of response (DpR). They determined ETS as percentage decrease in the sum of the longest diameters of the target lesions at the first evaluation of week 6 vs baseline, and defined DpR as the maximum percentage shrinkage during the study treatment. Of 685 study participants, they evaluated 632 who had the first tumor evaluation. Patients with ETS ≥ 20% showed longer progression-free survival (PFS) and overall survival (OS) vs those with ETS < 20%. In addition, DpR was identified to have significant association with PFS and OS.