Table 8.

Subgroup Analysis of OS and PFS.

Subgroup	Number of studies	Pooled HR (95%CI)	Heterogeneity
OS
Origin of ctDNA
Serum	2	3.07(1.51,6.25)	I2 = 0.0%, p = 0.947
Plasma	3	2.78(1.40, 5.53)	I2 = 71.9%,p = 0.029
FIGO stage
III/IV	3	3.37(2.15, 5.28)	I2 = 15.9%,p = 0.305
I-IV	2	1.82(1.24, 2.68)	I2 = 16.6%, p = 0.274
Detection methods
Real time-PCR	4	2.16(1.60, 2.93)	I2 = 8.7%,p = 0.350
Digital PCR	1	7.29(2.46, 21.59)	/
PFS
Origin of ctDNA
Serum	1	3.0 (1.44, 6.48)	/
Plasma	4	2.41 (1.70, 3.42)	I2 = 25.9%,p = 0.256
FIGO stage
III/IV	3	3.41(2.03, 5.72)	I2 = 0.0%, p = 0.426
I-IV	2	2.10(1.41, 3.13)	I2 = 0.0%, p = 0.456
Detection methods
Real time-PCR	3	2.28(1.60, 3.24)	I2 = 0%, p = 0.524
Digital PCR	2	3.76(1.84, 7.69)	I2 = 35.5%, p = 0.213