He et al. BMC Cancer 2010, 10:681 http://www.biomedcentral.com/1471-2407/10/681 Page 8 of 11 Figure 5 Relationship between the changing ratio in size of target lesion and OS among SD patients. Comparison of OS of SD patients stratified by a reduction in target lesion size of (a) 25%, (b) 20%, (c) 15%, (d) 10%, (e) 5%. and (f) 0%. SD stable disease; OS overall survival. correlated optimally with survival for patients with advanced NSCLC [25]. However, those studies do have several limitations, such as variation of treatment and their endpoint OS requires a long period of follow-up. Subsequent treatments might seriously interfere with OS, which cannot be regarded as evidence to guide early adjustment of first-line therapy. The current study uses similar treatment schemes and PFS as the primary