Comparative detection of lymph node micrometastases of stage II colorectal cancer by reverse transcriptase polymerase chain reaction and immunohistochemistry.
OBJECTIVE
Inconsistent conclusions have been drawn about the clinical significance of micrometastases in lymph nodes (LNs) of node-negative colorectal cancer (CRC) patients. We performed a comparative study of detection of micrometastases using immunohistochemistry (IHC) by anti-cytokeratin antibody and carcinoembryonic antigen (CEA)-specific reverse-transcriptase polymerase chain reaction (RT-PCR) in the same patients, in an attempt to move closer to their clinical application.


METHODS
Sixty-four CRC patients, with RNA of good quality available from paraffin-embedded LN specimens, were selected from 84 stage II patients who underwent curative surgery between 1988 and 1996. We investigated associations between the presence of micrometastases by each method and prognosis.


RESULTS
Micrometastases were detected in 19 (29.6%) of 64 patients by RT-PCR and in 35 (54.7%) of 64 patients by IHC. By RT-PCR analysis, patients exhibiting a positive band for CEA mRNA had a significantly worse prognosis than those who were RT-PCR-negative, with respect to both disease-free and overall survival (P =.027 and.015, respectively). By IHC analysis, the presence of micrometastasis did not predict patient outcome in terms of either disease-free or overall survival. Infiltrating pattern of tumor growth characteristic was significantly associated with shorter disease-free survival among various clinical or pathologic factors. By multivariate Cox regression analysis, micrometastasis detected by RT-PCR and the Crohn's-like lymphoid reaction were both independent prognostic factors.


CONCLUSIONS
Micrometastases detected by RT-PCR, but not IHC, may be of clinical value in identifying patients who may be at high risk for recurrence of CRC and who are therefore likely to benefit from systemic adjuvant therapy.
Noura
Shingo
S
Department of Surgery and Clinical Oncology, Graduate School of Medicine, Osaka University, Japan.
Yamamoto
Hirofumi
H
Ohnishi
Tadashi
T
Masuda
Norikazu
N
Matsumoto
Takashi
T
Takayama
Osamu
O
Fukunaga
Hiroki
H
Miyake
Yasuhiro
Y
Ikenaga
Masakazu
M
Ikeda
Masataka
M
Sekimoto
Mitsugu
M
Matsuura
Nariaki
N
Monden
Morito
M
D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology*; D000368:Aged; D002272:Carcinoembryonic Antigen / Q000032:analysis*; D015179:Colorectal Neoplasms / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis; D008207:Lymphatic Metastasis / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016019:Survival Analysis
D002272:Carcinoembryonic Antigen; D012333:RNA, Messenger; D007633:Keratins