Clinicopathological features of patients undergoing surgery for pancreatic cancer with very early postoperative recurrence

Table 1 Comparative baseline characteristics of the patients

Parameter	Overall (n = 279)	Group 1 (n = 28)	Group 2 (n = 251)	P value
Age, years (mean ± SD)	67.7 ± 16.61	65 ± 16.85	68 ± 9.58	< 0.001
Sex, n (%)				0.058
Male	175 (62.72)	17 (60.71)	158 (62.94)
Female	104 (37.28)	11 (39.29)	93 (37.06)
Cigarette smoking (current/ex), n (%)	216 (77.4)	22 (78.57)	172 (68.52)	0.02
Tumor location, n (%)
Head	245 (87.81)	25 (89.28)	220 (83.66)	0.031
Body/tail	29 (10.39)	3 (10.72)	26 (10.4)	0.039
RDW (%; median [range])	10.2 (7.5-16)	11 (7.7-14.5)	10.2 (7.5-16)	0.03
CA19-9 (U/mL; median [range])	256 (1.2-75000)	97.2 (1.2-5500)	255.9 (1.2-75000)	0.022

CA19-9: Carbohydrate antigen 19-9; SD: Standard deviation; RDW: Red cell distribution width.

Table 2 Univariate and multivariate analysis of parameters predicting very early recurrence

Parameter	Univariate OR (95%CI)	Univariate P value	Multivariate OR (95%CI)	Multivariate P value
Age (years)	1.012 (0.982-1.831)	< 0.001	1.141 (1.056-1.965)	0.024
Tumor location (head vs body/tail)	2.750 (1.585-4.214)	< 0.001	2.841 (1.656-7.021)	0.057
RDW (%)	3.041 (1.113-5.032)	< 0.001	3.505 (1.136-8.278)	0.079
CA19-9 (U/mL)	2.763 (1.557-4.005)	< 0.001	2.358 (1.505-4.964)	0.520
Tumor grade (G3)	1.625 (1.141-2.063)	< 0.001	2.43 (0.88-5.34)	< 0.001

CA19-9: Carbohydrate antigen 19-9; 95%CI: 95% confidence interval; OR: Odds ratio.

Table 3 Comparative postoperative outcomes of the patients, n (%)

Parameter	Overall (n = 279)	Group 1 (n = 28)	Group 2 (n = 251)	P value
Type of surgery				0.004
Pancreaticoduodenectomy	227 (81.36)	26 (92.85)	201 (80.07)
Left-sided pancreatectomy	28 (10.05)	2 (7.15)	26 (10.35)
Total pancreatectomy	24 (8.60)	0	24 (9.56)
Tumor grade				0.033
Mild (G1)	28 (10.05)	0	28 (11.15)
Moderate (G2)	110 (39.06)	2 (7.15)	108 (43.02)
Poor (G3)	141 (50.53)	26 (92.85)	115 (45.81)
Mortality (6 months)	39 (16.88)	9 (32.44)	30 (14.77)	0.032

Table 4 Independent predictors of very early recurrence

Parameter	Cut-off	OR	95%CI	Sensitivity (%)	Specificity (%)
G3 differentiation	-	2.43	0.88-5.34	62.8	83.0

95%CI: 95% confidence interval; OR: Odds ratio.

Table 5 Random-forest feature importance rankings

Feature	Importance
G3 differentiation	0.35
RDW	0.20
Tumor location (head)	0.15
Age	0.10
CA19-9	0.08

CA19-9: Carbohydrate antigen 19-9; RDW: Red cell distribution width.

Table 6 Ablation analysis of predictor contributions

Predictor	Contribution to predictive accuracy (%)
G3 differentiation	45
RDW	20
Tumor location (head)	15
Age	10
CA19-9	5

CA19-9: Carbohydrate antigen 19-9; RDW: Red cell distribution width.

Table 7 State-of-the-art comparison of very early recurrence studies in pancreatic ductal adenocarcinoma

Ref.	Sample size	VER definition	Key predictors	Statistical methods	Findings
Belfiori et al[6]	300	< 12 weeks	Body/tail tumors, G3 tumors	Logistic regression	Higher VER risk in body/tail (HR = 2.34)
Strobel et al[14]	500	< 6 months	G1 tumors (negative predictor)	Cox regression	G1 predicts long-term survival
Current study	303	< 12 weeks	G3 tumors, head tumors, RDW	Logistic regression, random forest	G3 strongest predictor (OR = 2.43), AUC 0.75 (random forest)

AUC: Area under the curve; HR: Hazard ratio; OR: Odds ratio; VER: Very early recurrence.