Evaluation of sentinel node concept in gastric cancer based on lymph node micrometastasis determined by reverse transcription-polymerase chain reaction.
OBJECTIVE
To determine the adequacy of sentinel node (SN) concept based on micrometastasis using immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR) in gastric cancer.


BACKGROUND
The SN concept has recently been introduced in gastrointestinal tract cancers. The precise detection of lymph node metastasis including micrometastasis is important for SN navigation surgery.


METHODS
Sixty-one patients with gastric cancer who were preoperatively diagnosed with T1-T2 (cT1-T2) and N0 (cN0) were enrolled. They underwent standard radical gastrectomy with lymph node dissection. One day before surgery, 4 mCi of (99m)Technetium-tin colloid was endoscopically injected into the submucosa around the tumor. During surgery, radioisotope uptake in the lymph node was measured using Navigator GPS. All dissected lymph nodes were examined by RT-PCR in addition to hematoxylin and eosin staining and IHC.


RESULTS
Sentinel nodes were identified in all patients (100%). The incidences of metastasis determined by hematoxylin and eosin and IHC were 8.2% (5 of 61) and 13.1% (8 of 61), respectively. Micrometastases undetectable by IHC were identified in 14 patients (23.0%) by RT-PCR. Only 1 patient had micrometastasis detectable by RT-PCR in lymph nodes other than SN, but this patient had a cT2 tumor. In patients with cT1 and cN0 tumors, the false negative and accuracy rates were 0% and 100%, respectively.


CONCLUSIONS
Although the incidence of micrometastasis detected by RT-PCR was quite high, SN navigation identified such metastasis in all patients except one. Thus, the SN concept was applicable to patients with cT1 and cN0 gastric cancer, even when micrometastasis was detectable by RT-PCR.
Department of Surgical Oncology and Digestive Surgery, Field of Oncology, Course of Advanced Therapeutics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan. arigami@m.kufm.kagoshima-u.ac.jp
Takaaki
T
Arigami
Shoji
S
Natsugoe
Yoshikazu
Y
Uenosono
Yuko
Y
Mataki
Katsuhiko
K
Ehi
Hiroshi
H
Higashi
Hideo
H
Arima
Shigehiro
S
Yanagida
Sumiya
S
Ishigami
Shuichi
S
Hokita
Takashi
T
Aikou
D000230:Adenocarcinoma / Q000235:genetics / Q000556:secondary*; D000368:Aged; D004273:DNA, Neoplasm / Q000032:analysis*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis / Q000175:diagnosis / Q000235:genetics; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013274:Stomach Neoplasms / Q000235:genetics / Q000473:pathology*
D004273:DNA, Neoplasm