Assessment of lymph node status in gallbladder cancer: location, number, or ratio of positive nodes

Abstract

A BACKGROUND: Assessment of lymph node status is a critical issue in the surgical management of gallbladder cancer. The aim of this study was to compare the anatomical location of positive nodes, number of positive nodes, and lymph node ratio (LNR) as prognostic predictors in gallbladder cancer.

Methods: We conducted a retrospective analysis of 135 patients with gallbladder cancer who underwent a radical resection with regional lymphadenectomy. A total of 2,245 regional lymph nodes were retrieved (median, 14 per patient). The location of positive nodes was classified according to the AJCC staging manual (7th edition). 'Optimal' cutoff values were determined for the number of positive nodes and LNR based on maximal χ(2) scores calculated with the Cox proportional hazards regression model.

Results: Lymph node metastasis was found histologically in 59 (44%) patients. The 'optimal' cutoff values for the number of positive nodes and LNR were determined to be three nodes and 10%, respectively. Univariate analysis identified location of positive nodes (pN0, pN1, pN2; P<0.001), number of positive nodes (0, 1 to 3, ≥ 4; P <0.001), and LNR (0%, 0 to 10%, >10%; P<0.001) as significant prognostic factors. Multivariate analysis identified number of positive nodes as an independent prognostic factor ( P=0.004); however, location of positive nodes and LNR failed to remain as an independent variable.

Conclusions: The number of positive lymph nodes better predicts patient outcome after resection than either the location of positive lymph nodes or LNR in gallbladder cancer. Dividing the number of positive lymph nodes into three categories (0, 1 to 3, or ≥ 4) is valid for stratifying patients based on the prognosis after resection.

Figure 1

Kaplan-Meier disease-specific survival estimates according to the presence or absence of regional nodal disease. The median survival time was not reached with a 5-year survival rate of 80% in patients without nodal disease, whereas the median survival time was 24 months with a 5-year survival rate of 37% in patients with nodal disease ( P < 0.001).

Figure 2

Kaplan-Meier disease-specific survival estimates according to the location of positive regional lymph nodes. The median survival time was not reached with a 5-year survival rate of 80% in patients without nodal disease (pN0). The median survival time was 74 months with a 5-year survival rate of 57% in patients with pN1 disease. The median survival time was 13 months with a 5-year survival rate of 23% in patients with pN2 disease. The survival post-resection differed significantly among the groups ( P < 0.001).

Figure 3

Kaplan-Meier disease-specific survival estimates according to the number of positive regional lymph nodes. The median survival time was not reached with a 5-year survival rate of 80% in patients without nodal disease. The median survival time was 63 months with a 5-year survival rate of 51% in patients with 1 to 3 positive nodes. The median survival time was 11 months with a 5-year survival rate of 10% in patients with ≥4 positive nodes. The survival post-resection differed significantly among the groups ( P < 0.001).

Figure 4

Kaplan-Meier disease-specific survival estimates according to the lymph node ratio (LNR) of regional lymph nodes. The median survival time was not reached with a 5-year survival rate of 80% in patients without nodal disease (LNR of 0%). The median survival time was 74 months with a 5-year survival rate of 60% in patients with a LNR of 0 to 10%. The median survival time was 15 months with a 5-year survival rate of 24% in patients with a LNR of > 10%. The survival post-resection differed significantly among the groups ( P < 0.001).