Active surveillance in metastatic pancreatic neuroendocrine tumors: A 20-year single-institutional experience

Table 1 Clinicopathological characteristics of patients with liver metastatic pancreatic neuroendocrine tumors, n (%)

	Number
Age (range, yr)	51 (18-69)
Gender
Male	41 (53.9)
Female	35 (46.1)
T stage
T1	5 (6.5)
T2	24 (31.2)
T3	25 (32.9)
T4	11 (14.4)
N stage
N0	36 (47.4)
N1	40 (52.6)
M stage at diagnosis
M0	31 (40.8)
M1	45 (59.2)
Grade of primary tumor
G1	13 (17.1)
G2	63 (82.9)
Grade of liver metastasis tumor
G1	12 (19.4)
G2	50 (80.6)
Surgery
Resection of primary tumor	51 (67.1)
Non-resection of primary tumor	25 (32.9)
Local treatment of liver metastasis
Yes (resection, TACE, ablation)	33 (43.4)
No local treatment	43 (56.6)
Max diameter of liver metastasis
< 5 mm	27 (35.5)
> 5 mm	49 (64.5)
Mean tumor burden of liver metastasis (range)	0.5% (0.03%-80%)

TACE: Transarterial chemoembolization.

Table 2 Univariate analysis of risk factors for time to progression in pancreatic neuroendocrine tumors

	95% Confidence interval
Univariate analysis	Hazard ratio	Lower	Upper
Largest axis of liver metastasis	2.718	1.375	5.372
Tumor burden of liver metastasis	2.262	1.064	4.81
Resection of primary tumor	2.112	1.015	4.394
T stage	1.888	1.208	2.952

Table 3 Multivariate analysis of risk factors for time to progression in pancreatic neuroendocrine tumors

	95% Confidence interval
Multivariate analysis	B	Standard error	Wald	Significant	Exp(B)	Lower	Upper
Largest axis of liver metastasis	0.810	0.395	4.206	0.040	2.247	1.037	4.872
Grade	0.614	0.384	2.559	0.110	1.848	0.871	3.924
T stage	0.793	0.362	4.810	0.028	2.211	1.088	4.492
Resection of primary tumor	0.888	0.394	5.076	0.024	2.431	1.123	5.266
Age	-0.284	0.364	0.608	0.436	0.753	0.369	1.536