Appropriate number of biliary biopsies and endoscopic retrograde cholangiopancreatography sessions for diagnosing biliary tract cancer

Table 1 Comparison of patient characteristics between the positive group and the negative group

	P group (n = 76)	N group (n = 19)	P value
Age (yr)	75 (29-90)	68 (43-82)	0.012
Males	60 (78.9)	12 (63.2)	0.229
Received antithrombotic drugs	14 (18.4)	0 (0)	0.064
Location of tumor (distal/hilar)	45/31	8/11	0.205
UICC stage (1/2/3/4)	27/29/10/10	7/7/3/2	0.91
Cholangitis within the last month	10 (13.2)	3 (15.8)	0.719

The values are shown as the median (range) or n (%). P: Positive; N: Negative; UICC: Union for International Cancer Control.

Table 2 Comparison of endoscopic retrograde cholangiopancreatography -related procedures between the positive group and the negative group

	P group (n = 76)	N group (n = 19)	P value
Number of ERCP sessions (1/2)	72/4	15/4	0.048
EST	74 (97.4)	17 (89.5)	0.177
Diagnosability of bile or brush or ENBD cytology	16/681 (23.5)	5/19 (26.3)	0.77
Cup diameter of biopsy forceps (1 mm/2 mm)	8/68	2/17	1.0
Total number of biopsies	2 (1 - 6)	2 (1 - 7)	0.039
Number of biopsies before biliary stenting	2 (1 - 4)	2 (1 - 3)	0.119
Number of biopsies after biliary stenting	2 (1 - 4)	1 (1 - 6)	0.065
PEP	4 (5.3)	0 (0)	0.58
Moderate	2
Severe	2

¹Biliary cytology, brush cytology and endoscopic nasobiliary drainage cytology were not performed in 8 patients in the P group. The values are shown as median (range) or n (%). ERCP: Endoscopic retrograde cholangiopancreatography; P: Positive; N: Negative; EST: Endoscopic sphincterotomy; ENBD: Endoscopic nasobiliary drainage; PEP: Post-ERCP pancreatitis.

Table 3 Univariate analysis of biliary biopsy positivity

	P group (n = 76)	N group (n = 19)	P value
Total number of biopsies ≤ 1	32 (42.1)	4 (21.1)	0.116
Total number of biopsies ≤ 2	62 (81.6)	12 (63.1)	0.120
Total number of biopsies ≤ 3	69 (90.8)	15 (78.9)	0.222
Number of ERCP sessions < 2	72 (94.7)	15 (78.9)	0.048

The values are shown as n (%). P: Positive; N: Negative; ERCP: Endoscopic retrograde cholangiopancreatography.

Table 4 Multivariate stepwise analysis of biliary biopsy positivity

	OR	95%CI	P value
Number of ERCP sessions < 2	4.8	1.08-21.4	0.04

OR: Odds ratio; CI: Confidential interval; ERCP: Endoscopic retrograde cholangiopancreatography.