For patients with Dukes' B (TNM Stage II) colorectal carcinoma, examination of six or fewer lymph nodes is related to poor prognosis.
BACKGROUND
Lymph node status is pivotal to the staging of colorectal carcinoma. The diagnosis of a lymph node negative tumor should imply a good prognosis; however, the outcomes for Dukes' B (TNM Stage II) patients remain variable, possibly in part due to understaging. The aim of this study was to determine whether examining a specified minimum number of lymph nodes using conventional techniques would eliminate the risk of understaging and thus have an effect on prognosis.


METHODS
Data on patients who underwent surgery for colorectal carcinoma at a single institution between 1985 and 1990 were reviewed. Patients with Dukes' B (TNM Stage II) or C (TNM Stage III) tumors and histologically confirmed disease-free resection margins who were treated with curative intent were included. Correlations among variables were assessed using the chi-square test, and survival comparisons were made using Kaplan-Meier curves and the log rank test. Multivariate analysis was performed using a Cox regression model.


RESULTS
Dukes' B (TNM Stage II) patients with < or =6 lymph nodes examined had significantly poorer overall survival than those with > or =7 lymph nodes examined (P = 0.0014). Such a significant difference was not observed among Dukes' C (TNM Stage III) patients (P = 0.7). Survival of Dukes' C patients was significantly worse compared with that of Dukes' B patients overall and Dukes' B patients with > or =7 lymph nodes examined (P < 0.0001). There was no significant difference in survival between Dukes' C and Dukes' B patients with < or =6 lymph nodes examined (P = 0.02). The number of examined lymph nodes was the only significant parameter correlated with survival in the multivariate analysis (P = 0.002).


CONCLUSIONS
Because Dukes' B patients with < or =6 examined lymph nodes have poorer outcomes than those with a higher number examined (probably due to understaging), the total number of examined lymph nodes should always be reported.
Department of Surgery, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
S
S
Caplin
J P
JP
Cerottini
F T
FT
Bosman
M T
MT
Constanda
J C
JC
Givel
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000401:mortality / Q000473:pathology*; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012044:Regression Analysis; D012737:Sex Factors; D016019:Survival Analysis