Fig. 1

Comparison of CTC positive rate before and after breast cancer surgery: meta-analysis. The heterogeneity of the recruited studies was estimated by the Cochran’s Q test (P = 0.147) and the I2 (27.5%). P value < 0.10 or I2 over 50% was defined as substantial heterogeneity. Hence, no substantial heterogeneity was observed among the studies and fixed model was used to analyze the overall difference of CTC positive rate before and after breast cancer surgery therapy (OR = 1.21, 95% CI: 1.06–1.39; P = 0.006). OR over 1 indicates increased CTC positive rate after surgery compared to preoperation