Quantification of FDG- and FLT-PET changes on PD0332991 and correlation with each other and time to progression. (A) Percent change in summed SUV_max for FDG among 16 evaluable patients. (B) Percent change in summed SUV_max for FLT among 16 evaluable patients. In panels A and B, the bar colors represent the best anatomic response achieved by International Working Group response criteria, as indicated in the legend. Asterisks denote patients who remained enrolled on PD0332991 for more than 1 year. (C) Percent changes in summed SUV_max of FDG and FLT plotted against one another. (D) Percent change in the summed FDG SUV_max in relation to time to progression. (E) Percent change in the summed FLT SUV_max in relation to time to progression. In panels C through E, the colors of the data points designate the best anatomic response by International Working Group criteria, as indicated in the legend. (F) Kaplan-Meier analysis of time to progression among patients who achieved < or ≥ 70% reduction in summed FLT SUV_max. (G) Representative images from patient 1, who achieved a reduction in FLT uptake after 3 weeks of PD0332991, but no metabolic response by FDG-PET, and whose best response was disease progression.