Table 3. Publication bias by Begg’s test and Egger’s test.

Clinicopathological features	Number of studies	Estimates	Begg’s test (P-value)	Egger’s test (P-value)	Publication bias
OS	17	HR + 95% CI	0.343	0.440	not significant
Gender	17	OR + 95% CI	0.837	0.514	not significant
Age	16	OR + 95% CI	0.260	0.181	not significant
Tumor size	6	OR + 95% CI	0.707	0.615	not significant
Differentiation	14	OR + 95% CI	0.044	0.013	significant
LNM	20	OR + 95% CI	0.206	0.130	not significant
TNM stage	17	OR + 95% CI	0.096	0.077	not significant
Smoking	6	OR + 95% CI	0.452	0.297	not significant
Pathological subtype	14	OR + 95% CI	0.155	0.064	not significant