Table 4. Main prognostic factors for survival and the pooled hazard ratios.

Prognostic factors	N	Patients	Heterogeneity (I-squared, P)	Model	Hazard ratio (95% CI)	P value
DFI (<3 years)	5	683	34.0%, 0.195	Fixed	1.70 (1.37-2.10)	0.000
Resection of metastases (incomplete)	4	670	25.1%, 0.261	Fixed	2.06 (1.63-2.62)	0.000
No. of pulmonary metastases (>1)	3	569	15.2%, 0.308	Fixed	1.31 (1.13-1.50)	0.000
The hormone receptor status of metastases (−)	6	302	0.0%, 0.623	Fixed	2.30 (1.43-3.70)	0.001

N, reference count; DFI, disease-free interval.