Table 1.

Patient characteristics by study period^*

		Early	Middle	Late	p value†	p value‡
Characteristic	Total	(1998–2003)	(2004–2009)	(2010–2015)	(among 3 groups)	(middle vs. late)
n	3707	794 (21)	1402 (38)	1511 (41)	-	-
Sex
Male	1932 (52)	414 (52)	716 (51)	802 (53)	0.56	0.28
Female	1775 (48)	380 (48)	686 (49)	709 (47)
Age, median (range), y	57 (3–89)	57 (3–88)	58 (4–88)	56 (4–89)	< 0.0001§	< 0.0001#
ASA-PS score ≥ 3	2612 (71)	314 (42)	1036 (74)	1262 (84)	< 0.0001	< 0.0001
BMI, median (range), kg/m2	27 (11–68)	27 (11–68)	27 (14–59)	27 (15–55)	0.019§	0.69#
≥ 30	1080 (30)	189 (25)	417 (30)	474 (31)	0.01	0.36
Cirrhosis	103 (3)	33 (4)	40 (3)	30 (2)	0.04	0.29
Disease
Hepatocellular carcinoma	258 (7)	67 (8)	93 (7)	98 (6)	0.18	0.88
Biliary carcinoma	295 (8)	57 (7)	109 (8)	129 (9)	0.49	0.46
CRLM	2144 (58)	452 (57)	782 (56)	910 (60)	0.04	0.02
NELM	259 (7)	57 (7)	128 (9)	74 (5)	< 0.0001	<.00001
Non-CR/non-NE LM	646 (17)	135 (17)	250 (18)	261 (17)	0.87	0.70
Benign lesion	105 (3)	26 (3)	40 (3)	39 (3)	0.63	0.73
CRLM (n=2144)
Preoperative chemotherapy	1757 (82)	314 (70)	637 (82)	806 (89)	< 0.0001	< 0.0001
Tumor number, median (range)	2 (1–76)	1 (1–15)	2 (1–76)	2 (1–41)	0.002§	0.8#
Maximum tumor size, median (range), mm	20 (1–210)	20 (2–150)	20 (1–210)	22 (1–180)	0.04§	0.5#

^*Values in table are number of patients (percentage) unless indicated otherwise

^†χ2 test unless indicated otherwise

^‡Fisher exact test unless indicated otherwise

^§Kruskal-Wallis test

^#Mann-Whitney U test

ASA-PS, American Society of Anesthesiologists physical status; BMI, body mass index

CRLM, colorectal liver metastasis; NELM, neuroendocrine liver metastasis

Non-CR/non-NE LM, non-colorectal/non-neuroendocrine liver metastasis