Lymph node ratio and preoperative CA 19-9 levels predict overall survival and recurrence-free survival in patients with resected pancreatic adenocarcinoma

Abstract

Aim: Clinicopathologic factors predicting overall survival (OS) would help identify a subset to benefit from adjuvant therapy.

Methods: One hundred and sixty-nine patients patients from 1984 to 2009 with curative resections for pancreatic adenocarcinoma were included. Tumors were staged by American Joint Committee on Cancer 7th edition criteria. Univariate and multivariable analyses were performed using Kaplan-Meier methodology or Cox proportional hazard models. Log-rank tests were performed. Statistical inferences were assessed by two-sided 5% significance level.

Results: Median age was 67.1 (57.2-73.0) years with equal gender distribution. Tumors were in the head (89.3%) or body/tail (10.7%). On univariate analysis, adjuvant therapy, lymph node (LN) ratio, histologic grade, negative margin status, absence of peripancreatic extension, and T stage were associated with improved OS. Adjuvant therapy, LN ratio, histologic grade, number of nodes examined, negative LN status, and absence of peripancreatic extension were associated with improved recurrence-free survival (RFS). On multivariable analysis, LN ratio and carbohydrate antigen (CA) 19-9 levels were associated with OS. LN ratio was associated with RFS.

Conclusion: The LN ratio and CA 19-9 levels are independent prognostic factors following curative resections of pancreatic cancer.

Keywords: Carbohydrate antigen 19-9; Lymph node ratio; Overall survival; Pancreatic adenocarcinoma; Recurrence-free survival.

Figure 1

Kaplan-Meier curves. A, B: Univariate analysis Kaplan-Meier curve of adjuvant therapy demonstrates improvements in overall survival (OS) (P = 0.012), but not recurrence-free survival (RFS). The protective effect of adjuvant therapy was lost on multivariate analysis (n = 169); C, D: Univariate analysis Kaplan-Meier curves of lymph node ratio using an arbitrary stratification (0, < 0.2, 0.2-0.4 and > 0.4) shows significant improvements in OS (P = 0.002) and RFS (P = 0.001) (n = 169); E, F: Multivariate analysis Kaplan-Meier curves of peroperative carbohydrate antigen (CA) 19-9 levels using an arbitrary cutoff of 370 U/mL demonstrate no correlation with OS (P = 0.137) and marginal improvement in RFS (P = 0.086) (n = 124).

Figure 2

Hazard ratios of variables analyzed on multivariable analysis for overall survival (A) and recurrence-free survival (B). CA: Carbohydrate antigen; Neg: Negative; Pos: Positive.