Figure 5.

Tumor growth delay studies demonstrating the effects of a single 10 Gy dose alone or in combination with a 250 mg/kg dose of metformin administered i.p. either 1 h prior to or following irradiation of SA-NH tumors grown in the flanks of C3H mice. Treatment of tumors began when they reached an average size of approximately 250 mm³ and growth measurements ended after they exceeded 1000 mm³ in size. An untreated control group was also monitored for comparison. Each metformin plus radiation treated tumor group is compared to the radiation only group. Mean growth times and SEM were determined. Mean tumor volumes over time were compared among groups using repeated measures analysis of covariance (ANCOVA) assuming a quadratic model and accounting for separate variances in each group. A post-hoc pairwise comparison among groups was performed using the Tukey-Kramer method. Time to reach 1000 mm³ in size in each group was estimated using a Kaplan-Meier curve and compared between groups using the log rank test.