Prognostic impact of regional lymph node micrometastasis in patients with node-negative biliary cancer.
OBJECTIVE
To immunohistochemically identify regional lymph node micrometastases in patients with regional node-negative biliary cancer who underwent curative resection, and to evaluate their clinical significance.


BACKGROUND
The clinical significance of immunohistochemically detected lymph node micrometastasis has recently been evaluated in various tumors. However, few reports have focused on this issue with regard to biliary cancer.


METHODS
A total of 1421 regional lymph nodes from 151 patients with biliary cancer with negative regional nodes (as determined by conventional methods) were immunostained with antibody against cytokeratins 7 and 8 (CAM5.2). Prognostic impact was evaluated among patients with no metastasis, micrometastasis, and obvious metastasis detected by hematoxylin and eosin staining. Immunostained tumor foci were classified as small micrometastasis or large micrometastasis according to size (above or below 0.2 mm).


RESULTS
CAM5.2-positive occult carcinoma cells in regional lymph nodes were detected in 33 (22%) of 151 patients and 49 (3%) of 1421 regional lymph nodes. Small micrometastases were detected in 23 patients, whereas large micrometastases were found in 10 patients. Survival for patients with micrometastasis was significantly worse than that for patients without (P = 0.0051), but was significantly better than that for patients with overt metastasis (P = 0.0092). No significant difference in postoperative survival was seen between patients with small and large micrometastases (P = 0.4221).


CONCLUSIONS
Occult cancer cells were present in regional lymph nodes of 22% patients with regional node-negative biliary cancer, and were associated with significantly worse survival. Patients with micrometastases should be treated as carefully as node-positive patients.
Yonemori
Atsuya
A
Department of Surgical Oncology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Kondo
Satoshi
S
Matsuno
Yoshihiro
Y
Ito
Tomoo
T
Nakanishi
Yoshitsugu
Y
Miyamoto
Masaki
M
Tanaka
Eiichi
E
Hirano
Satoshi
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001661:Biliary Tract Neoplasms / Q000401:mortality* / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053552:Keratin-7 / Q000032:analysis / Q000276:immunology; D053533:Keratin-8 / Q000032:analysis / Q000276:immunology; D008198:Lymph Nodes / Q000737:chemistry / Q000473:pathology; D008207:Lymphatic Metastasis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D015996:Survival Rate
D053552:Keratin-7; D053533:Keratin-8