Statistical analysis

Statistical differences in Kaplan Meier survival curves were evaluated with log rank testing and hazard ratio estimation. Tumor growth curves were analyzed by fitting segmental linear (broken stick) model with two segments [21, 22]. Briefly, time to accelerated or fast growth is a model parameter defined as the “changepoint” or “breakpoint” and is the time at which tumor started to grow at a faster average rate. Pairwise Mann Whitney test was used to test differences in medians and F- test was used to compare standard deviations, for comparisons of means pairwise t test was used. Significance of linear trend between groups was evaluated with linear trend test. P values less than 0.05 were considered significant, all P values were two sided. Sample size was estimated by using Mead’s resource equation. Allocation was done by using complete randomization. All statistical analysis was done in Grapad Prism 6.07 software (GraphPad Software, La Jolla, CA, USA).