Comparison of prognostic factors and their differences in intrahepatic, hilar, and distal cholangiocarcinoma: A systematic review and meta-analysis

Table 1 Baseline characteristics of all studies included

Ref.	Country	Study period	Study design	No. patients based on tumor location			Patient source	Tumor classification criteria	Follow up (month)	Quality score (NOS)
				IHCC	PHCC	DCC
DeOliveira et al[15]	America	1973-2004	Triple-arm	44	281	239	Johns Hopkins Hospital	NA	Median follow up: 29	7
Murakami et al[8]	Japan	1990-2009	Triple-arm	21	50	56	Hiroshima University Hospital	UICC, 7th edition	Median follow up: 78 (2-254)	7
Yusoff et al[16]	Malaysia	1997-2007	Triple-arm	12	38	19	A tertiary referral center in Malaysia	TNM staging, 2002	NA	7
Ercolani et al[17]	Italy	1985-2011	Triple-arm	136	150	53	Two Italian tertiary referral University Centers	AJCC, 7th edition	Median follow up: 30.2 ± 38	8
Waseem and Tushar[18]	America	1992-2010	Triple-arm	90	104	48	Mayo Clinic	UICC, 7th edition	Median follow up: 11.6 (3.1-24.3)	9
Guglielmi et al[19]	Italy	1990-2007	Two-arm	33	62	None	University of Verona Medical School	AJCC, 7th edition	Every 6 months	8
Hang et al[20]	China	1973-2015	Triple-arm	5462	5626	622	SEER database + TCGA database	NA	NA	7
Nakanishi et al[21]	Japan	1998-2018	Two-arm	None	236	130	Hokkaido University Hospital	AJCC, 8th edition	Every 3–6 months	8
Sallinen et al[22]	Finland	2000-2015	Two-arm	None	36	47	A tertiary hospital in Finland	AJCC, 7th edition	NA	7
Istanbouli et al[23]	America	1995-2016	Triple-arm	64	75	31	Mayo Clinic	AJCC, 7th edition	NA	7
Sarkhampee et al[24]	Thailand	2013-2018	Triple-arm	398	237	85	Sunpasitthiprasong Hospital	AJCC, 7th edition	3 to 6 months during the first 2 years. Then every 6 to 12 months thereafter	8

IHCC: Intrahepatic cholangiocarcinoma; PHCC: Peri-hilar cholangiocarcinoma; DCC: Distal cholangiocarcinoma; UICC: International Union Against Cancer; AJCC: American Joint Committee on Cancer; NOS: Newcastle Ottawa Scale.

Table 2 Pooled results of all available studies in measured outcomes

Measured outcomes	No. studies	No. patients		Model (fixed/random)	OR/HR	95%CI	P (overall test)	Heterogeneity		Begg test	Egger test
								I2	P value	Pr >|z1	P >|t|1
Overall survival	9	IHCC: 6296	PHCC: 6716	Random	HR = 1.02	0.83-1.24	P = 0.88	58%	0.01	1	0.137
Node metastasis	6	IHCC: 651	PHCC: 817	Fixed	OR = 0.69	0.55-0.88	P = 0.003	0%	0.85	0.469	0.492
Neural invasion	3	IHCC: 435	PHCC: 382	Random	OR = 0.71	0.11-4.64	P = 0.72	96%	< 0.00001	1	0.671
Vascular invasion	3	IHCC: 453	PHCC: 384	Random	OR = 0.82	0.28-2.38	P = 0.72	90%	< 0.0001	1	0.657
Overall survival	8	IHCC: 6227	DCC: 1153	Random	HR = 1.07	0.18-1.36	P = 0.59	56%	0.03	0.533	0.355
Node metastasis	5	IHCC: 522	DCC: 445	Fixed	OR = 0.33	0.23-0.45	P = 0.00001	70%	0.009	0.816	0.631
Neural invasion	-	-	-	-	-	-	-	-	-	-	-
Vascular invasion	3	IHCC: 661	DCC: 250	Fixed	OR = 1.66	1.22-2.28	P = 0.001	91%	< 0.0001	0.333	0.263
Overall survival	10	PHCC: 6833	DCC: 1330	Random	HR = 1.06	0.92-1.22	P = 0.42	41%	0.09	1	0.352
Node metastasis	7	PHCC: 989	DCC: 622	Random	OR = 0.48	0.29-0.81	P = 0.005	80%	< 0.0001	0.381	0.952
Neural invasion	3	PHCC: 573	DCC: 250	Random	OR = 2.35	0.76-7.28	P = 0.14	90%	< 0.0001	0.333	0.065
Vascular invasion	-	-	-	-	-	-	-	-	-	-	-

¹P value for statistical tests (e.g., Begg and Egger tests).

IHCC: Intrahepatic cholangiocarcinoma; PHCC: Peri-hilar cholangiocarcinoma; DCC: Distal cholangiocarcinoma.