Sentinel lymph node detection with Tc-99m tin colloids in patients with esophagogastric cancer.
BACKGROUND
The aim of this study was to determine by radioisotope use whether the sentinel lymph node concept is applicable to esophagogastric cancers. In addition, we examined radioactivities of hot nodes and compared them with the sensitivity of a gamma probe.


METHODS
The subjects were 44 patients, 23 with esophageal cancer and 21 with gastric cancer. The day before surgery, patients underwent endoscopic submucosal injection of 184 MBq of Tc-99m tin colloids into sites surrounding the tumor. Radioisotope activities of lymph nodes dissected at surgery were measured with a well-typed gamma detector and each lymph node was categorized as a hot or cold node. Histopathology of the lymph nodes was examined by hematoxylin and eosin staining. Radioisotope activities and histopathological results were compared to determine whether radioisotope flow reflects lymphatic flow to regional lymph nodes. The sensitivity of a gamma probe was measured in a laboratory study and the relation between the radioisotope activities of hot nodes and the detection sensitivity of the gamma probe was examined.


RESULTS
Histopathological examination revealed lymph node metastasis in 18 of the 44 patients. In 15 of these 18 patients, metastatic foci were recognized in at least one hot node. Subsequent analysis was performed on the 36 patients in whom tumor invasion was confined to the muscle layer and in whom endoscopic clippings had not been applied. Lymph node metastases were observed in 12 of these 36 patients. In these 12 patients, at least one hot node was positive for metastasis. The laboratory study revealed that the gamma probe was able to detect radioisotope activities of >/=0.02 micro Ci. Thirty-two of 63 (51%) esophageal cancer hot nodes and 16 of 86 (19%) gastric cancer hot nodes showed radioisotope activities below the detection sensitivity of the gamma probe.


CONCLUSIONS
The sentinel lymph node concept is applicable to patients with esophageal and gastric cancers; however, further studies are necessary to identify hot nodes accurately using gamma probes.
Yasuda
Seiei
S
Department of Surgery, Tokai University School of Medicine, Isehara, Kanagawa, Japan. yasuda@is.icc.u-tokai.ac.jp
Shimada
Hideo
H
Chino
Osamu
O
Tanaka
Hikaru
H
Kenmochi
Takahiro
T
Takechi
Masahiko
M
Nabeshima
Kazuhito
K
Okamoto
Yuichi
Y
Kato
Yuko
Y
Kijima
Hiroshi
H
Suzuki
Yutaka
Y
Ogoshi
Kyoji
K
Tajima
Tomoo
T
Makuuchi
Hiroyasu
H
D003102:Colloids; D004938:Esophageal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D008207:Lymphatic Metastasis; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D017556:Technetium Compounds; D017971:Tin Compounds
D003102:Colloids; D019275:Radiopharmaceuticals; D017556:Technetium Compounds; D017971:Tin Compounds; C033493:technetium Tc 99m tin colloid