J Korean Surg Soc.  2011 Apr;80(4):260-266. 10.4174/jkss.2011.80.4.260.

Prognostic implication of metastatic lymph node ratio in node-positive rectal cancer

• Lee SM
• Shin JS
• Choi HJ
• Park KJ
• Roh YH
• Kwon HC
• Roh MS
• Lee HS
• Kim C

• KMID: 1820016
• DOI: http://doi.org/10.4174/jkss.2011.80.4.260

Abstract

PURPOSE
The aim of this study was to evaluate the prognostic significance of the ratio between metastatic and examined lymph nodes (LNs) in patients with stage III rectal cancer.
METHODS
A review was made of 175 (male, 98) patients with stage III rectal cancer of R0 resection. LN disease was stratified both by the American Joint Committee on Cancer/International Union Against Cancer nodal classification (pN) and by quartiles of the lymph node ratio (LNR). Disease-free survivals (DFS) were made using Kaplan-Meier curves and assessed by the log rank test and multivariate analysis was performed using the Cox proportional hazards model.
RESULTS
Patients ranged in age from 29 to 83 (median, 60) years with median follow-up of 47 months (range, 13 to 181 months). months. There was a significant correlation between the number of metastatic LNs and the LNR (r = 0.8681, P < 0.0001). Cut-off points of LNR quartiles best to separate patients with regard to 5-year DFS were between quartile 2 and 3, and between 3 and 4 (LNR1, 2, and 3); the 5-year DFS according to such stratification was 89.6%, 55.8%, and 18.2% in LNR1, 2, and 3, respectively (P < 0.0001). Cox model identified the LNR as the most significant independent prognostic covariate; LNR2 showed 3.6 times (95% confidence interval [CI], 1.682 to 7.584; P = 0.0009) and LNR3, 18.7 times (95% CI, 6.872 to 50.664; P < 0.0001) more risky than LNR1.
CONCLUSION
This study suggests that ratio-based LN staging, which reflects the number of LNs examined and the quality of LN dissection, is a simple and reliable system for prognostic LN stratification in patients with stage III rectal cancer.

Keyword

Rectal cancer; Metastatic lymph node ratio; Prognostic factor

MeSH Terms

Disease-Free Survival
Follow-Up Studies
Humans
Joints
Lymph Nodes
Multivariate Analysis
Rectal Neoplasms

Figure

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  Fig. 1 The correlation between the metastatic lymph node ratio and number of lymph node metastases. The lymph node ratio is closely correlated with the number of lymph node metastases (Pearson correlation coefficient, 0.8681; P < 0.0001).

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  Fig. 2 Kaplan-Meier survival curves for 4 groups based on quartiles of the distribution of metastatic lymph node ratio. Differences in 5-year disease-free survivals between quartile (Q) 2 and 3 and between 3 and 4 were statistically significant (P < 0.0001, each).

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  Fig. 3 Kaplan-Meier survival curves for the ratio-based staging. Five-year disease-free survival was 89.6%, 55.8%, and 18.2% for lymph node ratio (LNR)1, LNR2, and LNR3, respectively (P < 0.0001).

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