CT lymphography for sentinel lymph node mapping of clinically N0 early oral cancer

Background The objectives of this retrospective study were to evaluate the usefulness of computed tomography lymphography (CTL) and to clarify the optimal timing of CTL in sentinel lymph node (SLN) mapping of clinically N0 early oral cancer. Methods Twenty patients with clinically N0 early oral cancer underwent CTL with a 128 multi-detector row CT scanner to detect SLN the day before resection of primary tumor and SLN biopsy with indocyanine green (ICG) fluorescence guidance. CT scanning was performed in the first 10 patients at 2, 5, and 10 min after submucosal injection of iopamidol and in the remaining 10 patients at 2, 3.5, 5, and 10 min after the injection of contrast medium. We evaluated the SLN detection rate at each scan timing and the number and location of SLNs. We evaluated whether CTL-enhanced SLNs could be identified intraoperatively as ICG fluorescent lymph nodes. Results SLNs were detected by CTL in 19 of the 20 patients (95.0%), and the mean number of SLNs was 2 (range, 1-4). All SLNs were located on the ipsilateral side; 35 of 37 SLNs were located at level I and II, and 2 SLNs were lingual lymph nodes. All SLNs could be detected 2 min and 3.5-5 min after contrast medium injection, and CTL-enhanced SLNs could be identified intraoperatively as fluorescent lymph nodes. Conclusions CTL could facilitate the detection of SLNs in early oral cancer, and the optimal timing of CT scanning was at 2 and 5 min after injection of contrast medium.