Metastatic lymph node size and colorectal cancer prognosis.
BACKGROUND
Colorectal cancer patients with lymph node metastasis constitute a heterogeneous population with variable prognoses. In this study, my colleagues and I propose a simpler lymph node (LN) staging system for colorectal cancer.


METHODS
Four-hundred and twenty-three consecutive colorectal cancer patients were studied. Of these, 36 were excluded because another carcinoma was present. The remaining 387 patients entered the TNM staging analysis. In the survival analysis, 76 patients with distant metastasis were excluded and the remaining 311 patients (LN(-) = 204 and LN(+) = 107) were studied. The diameter of the largest metastatic LN (MLN) was measured on histopathological slides. After examination of various cutpoints and survival outcomes, patients with MLNs were classified into n1 (< or = 9 mm) and n2 (> or = 10 mm) groups, according to size of MLNs (n-stage).


RESULTS
Using disease-free survival (DFS) and overall survival (OS) as outcomes, patients were separated into significant prognostic groups by MLN size (univariate, p < 0.0001) (5-year survival, DFS: n0 = 91.5%, n1 = 62.2%, and n2 = 34.4%; OS: n0 = 85.1%, n1 = 63.5%, and n2 = 42.5%) and International Union Against Cancer/American Joint Committee on Cancer (UICC/AJCC) (N-stage) (univariate, p < 0.0001) (5-year survival, DFS: N0 = 91.5%, N1 = 60.5%, and N2 = 36.8%; OS: N0 = 85.1%, N1 = 65.3%, and N2 = 38.0%). But in patients with fewer than 15 LNs examined (n = 31), only the new nodal stage stratified patients into significant groups (OS: p = 0.003 and DFS: p = 0.001). Only the UICC/AJCC N-stage subcategories were further split into significant prognostic groups by MLN size (UICC/AJCC N1: DFS, p = 0.048 and OS, p = 0.11; N2: DFS, p = 0.04 and OS, p = 0.04). n-stage was an independent important factor both in the DFS and OS in multivariable analysis.


CONCLUSIONS
MLN size is a strong prognostic variable in colorectal carcinoma. This new metric may help clinicians treating colorectal cancer patients, but additional studies are required before clinical application.
Dhar
Dipok Kumar
DK
Department of Digestive and General Surgery, Shimane University, Izumo 693-8501, Japan.
Yoshimura
Hiroshi
H
Kinukawa
Naoko
N
Maruyama
Riruke
R
Tachibana
Mitsuo
M
Kohno
Hitoshi
H
Kubota
Hirofumi
H
Nagasue
Naofumi
N
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000401:mortality* / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D009929:Organ Size; D015996:Survival Rate