High prevalence of isolated tumour cells in regional lymph nodes from pN0 colorectal cancer.
BACKGROUND
The prevalence of isolated tumour cells (ITCs) in regional lymph nodes from colorectal cancer (CRC) is controversial and has never been prospectively assessed in large groups of consecutive patients. pN0 early-relapsing CRC can be explained by lymph node-ITC.


OBJECTIVE
To assess the prevalence of ITCs in regional lymph nodes from 309 consecutive patients with pN0M0 (pathological (p)-tumour-node-metastasis (TNM) staging system) CRCs.


METHODS
ITCs were assessed by immunohistochemistry (MNF116 monoclonal antibody (1:100); Dako, Glostrup, Denmark) in two serial histological sections obtained from 5016 mesenteric lymph nodes from 309 patients with pN0 CRCs (mean number of lymph nodes per patient = 16.2; p-TNM stage 0, n = 25; p-TNM stage I, n = 123; and p-TNM stage II (A+B), n = 161). Tumour histology, vascular cancer invasion and pathological stage were also recorded.


RESULTS
ITCs were detected in the regional lymph nodes of 156 of 309 (50.5%) patients with CRC, mostly in nodes located within 3 cm from the neoplasia. ITC status correlated with (a) tumour p-TNM stage (Pearson's chi(2): p<0; ordered logistic regression: odds ratio (OR) = 4.6; 95% confidence interval (CI) = 2.88 to 7.33; p<0) and (b) pT value (Pearson's chi(2): p = 0; ordered logistic regression: OR = 4.9; 95% CI = 3.1 to 7.7; p<0). By multivariate analysis, including p-TNM stage, vascular invasion and ITC status, both stage (OR = 5.1; 95% CI = 2.9 to 8.9; p<0) and vascular invasion (OR = 4.2; 95% CI = 1.94 to 8.98; p<0) were found to be independent variables associated with ITC+ lymph nodes.


CONCLUSIONS
More than 50% of pN0-CRC patients have ITCs in the mesenteric lymph nodes. ITC status is significantly correlated with cancer stage and vascular cancer invasion. The clinicopathological effect of ITC remains to be prospectively evaluated.
Mescoli
C
C
Department of Diagnostic Sciences & Special Therapies, Pathology Unit, Istituto Oncologico Veneto-IRCCS, Università degli Studi di Padova, Padova, Italy.
Rugge
M
M
Pucciarelli
S
S
Russo
V M
VM
Pennelli
G
G
Guido
M
M
Nitti
D
D
D000230:Adenocarcinoma / Q000473:pathology / Q000556:secondary* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001808:Blood Vessels / Q000473:pathology; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008643:Mesentery; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011446:Prospective Studies