Detection of pleural lymph flow using indocyanine green fluorescence imaging in non-small cell lung cancer surgery: a preliminary study.
OBJECTIVE
Lymphatic spread of lung carcinoma to the mediastinum is a key determinant of prognosis. The lymph flow often carries metastases from the pulmonary segment directly into the mediastinal lymph nodes, without passing through the hilar nodes. This phenomenon is termed as "skip metastasis." This study investigated the subpleural lymphatic flow to the mediastinum using indocyanine green (ICG) with a near-infrared fluorescence imaging system.


METHODS
Seventeen patients with lung cancer were enrolled in this study. A 0.3 ml sample of solution containing the fluorescent dye ICG (5 mg/ml) was injected into subpleural sites near the primary tumor. Fluorescence imaging was used to monitor the flow of ICG-containing lymph from the injection site for 5 min. The relationship between the anatomical segment of the primary tumor and the lymphatic flow was assessed.


RESULTS
The lymphatic vessels draining from the injection site were revealed by the bright ICG fluorescence in 14 of the patients (82.4 %). A direct lymphatic flow to the mediastinum was confirmed in 3 of those 14 (21.4 %).


CONCLUSIONS
These findings confirm the direct flow of lymph to the mediastinum without passage through the hilum pulmonis intraoperatively. These preliminary results may provide a valuable clue for further investigations of the mechanisms underlying skip metastasis.
Department of Chest, Breast and Endocrinologic Surgery, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, 010-8543, Japan. i-karo@mui.biglobe.ne.jp
Kazuhiro
K
Imai
Yoshihiro
Y
Minamiya
Hajime
H
Saito
Taku
T
Nakagawa
Manabu
M
Ito
Takashi
T
Ono
Satoru
S
Motoyama
Yusuke
Y
Sato
Hayato
H
Konno
Jun-ichi
J
Ogawa
D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000556:secondary / Q000601:surgery; D004396:Coloring Agents; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007208:Indocyanine Green; D007432:Intraoperative Period; D008175:Lung Neoplasms / Q000098:blood supply / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis / Q000175:diagnosis; D042601:Lymphatic Vessels / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D061848:Optical Imaging / Q000379:methods; D010994:Pleura / Q000098:blood supply*; D011013:Pneumonectomy; D012189:Retrospective Studies; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*
D004396:Coloring Agents; D007208:Indocyanine Green