Open Access Research

Evaluation of lymph node numbers for adequate staging of Stage II and III colon cancer

Chandrakumar Shanmugam1, Robert B Hines2, Nirag C Jhala3, Venkat R Katkoori1, Bin Zhang4, James A Posey57, Harvey L Bumpers6, William E Grizzle17, Isam E Eltoum17, Gene P Siegal17 and Upender Manne17*

Author Affiliations

1 Departments of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA

2 Jiann-Ping Hsu College of Public Health, Georgia Southern University, Statesboro, GA 30460, USA

3 Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA

4 Department of Biostatistics, University of Alabama at Birmingham, Birmingham, AL35294, USA

5 Department of Medicine, University of Alabama at Birmingham, Birmingham, AL35294, USA

6 Department of Surgery, Morehouse School of Medicine, Atlanta, GA 30310, USA

7 Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA

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Journal of Hematology & Oncology 2011, 4:25  doi:10.1186/1756-8722-4-25

Published: 28 May 2011

Abstract

Background

Although evaluation of at least 12 lymph nodes (LNs) is recommended as the minimum number of nodes required for accurate staging of colon cancer patients, there is disagreement on what constitutes an adequate identification of such LNs.

Methods

To evaluate the minimum number of LNs for adequate staging of Stage II and III colon cancer, 490 patients were categorized into groups based on 1-6, 7-11, 12-19, and ≥ 20 LNs collected.

Results

For patients with Stage II or III disease, examination of 12 LNs was not significantly associated with recurrence or mortality. For Stage II (HR = 0.33; 95% CI, 0.12-0.91), but not for Stage III patients (HR = 1.59; 95% CI, 0.54-4.64), examination of ≥20 LNs was associated with a reduced risk of recurrence within 2 years. However, examination of ≥20 LNs had a 55% (Stage II, HR = 0.45; 95% CI, 0.23-0.87) and a 31% (Stage III, HR = 0.69; 95% CI, 0.38-1.26) decreased risk of mortality, respectively. For each six additional LNs examined from Stage III patients, there was a 19% increased probability of finding a positive LN (parameter estimate = 0.18510, p < 0.0001). For Stage II and III colon cancers, there was improved survival and a decreased risk of recurrence with an increased number of LNs examined, regardless of the cutoff-points. Examination of ≥7 or ≥12 LNs had similar outcomes, but there were significant outcome benefits at the ≥20 cutoff-point only for Stage II patients. For Stage III patients, examination of 6 additional LNs detected one additional positive LN.

Conclusions

Thus, the 12 LN cut-off point cannot be supported as requisite in determining adequate staging of colon cancer based on current data. However, a minimum of 6 LNs should be examined for adequate staging of Stage II and III colon cancer patients.

Keywords:
Colon cancer; Clinical outcomes; Lymph nodes; Stage II; Stage III