Pancreatic neuroendocrine tumors: Are tumors smaller than 2 cm truly indolent?

Table 1 Patient characteristics, %

Variable	PNET ≥ 2 cm, n = 42	PNET < 2 cm, n = 22	P value
Mean age (yr)	49.1	52.4	0.32
Sex (fraction of females)	64.3	59.1	-
Whipple vs DP	31 vs 62	27 vs 68	-
Recurrence rate	21.4	18.2	0.98
Mitosis > 3/10 HPF	58.1	26.3	0.05
Ki67 index > 3	51.5	31.6	0.79
CK19 positive	69.2	35.7	0.08
Lymph node involvement	30.8	0	0.01
Perineural invasion	16.7	9.1	0.65
Lymphovascular invasion	21.4	9.1	0.37

DP: Distal pancreatectomy; PNET: Pancreatic neuroendocrine tumors; HPF: High-power field.

Table 2 Variables associated with a higher risk of mortality

Variable	HR (raw)	Statistical significance (P value)	Multivariate analysis (P value)
PNET ≥ 2 cm	0.878	NS	NS
PNET < 2 cm	1
Mitosis > 3/10 HPF	5.862	NS	NS
Mitosis < 3/10 HPF	1
Ki67 index > 3%	63.594	NS	NS
Ki67 index < 3%	1
Lymph node involvement (+)	5.688	< 0.05	NS
Lymph node involvement (-)	1
Perineural invasion (+)	6.448	< 0.05	NS
Perineural invasion (-)	1
Lymphovascular invasion (+)	24.875	< 0.05	NS
Lymphovascular invasion (-)	1

HR: Hazard ratios; NS: Not statistically significant; PNET: Pancreatic neuroendocrine tumors; HPF: High-power field.