The incidence, risk factors, and new prediction score for fluorescence abnormalities of near-infrared imaging using indocyanine green in laparoscopic low anterior resection for rectal cancer

Purpose: Several studies have reported the efficacy of near-infrared imaging using indocyanine green in laparoscopic low anterior resection (LAR), but a detailed examination of its fluorescence abnormalities is still insufficient. The purpose of this study was to clarify the incidence of fluorescence abnormalities and to create a new prediction score in laparoscopic LAR.

Methods: This was a retrospective, multicenter study that included patients with rectal cancer who underwent laparoscopic LAR from September 2014 to November 2018.

Results: A total of 336 patients were included. The transection line was changed due to fluorescence abnormalities in 5.4% (18/336) of cases, and the median length of additional resection was 70 mm. Anastomotic leakage of Clavien-Dindo grade ≥ II occurred in 6.0% (20/336). The gender and the intraoperative pre-planned proximal margin (IpPM) were significant factors for fluorescence abnormalities. We devised the fluorescence abnormality prediction score (FAPS) derived from the gender, IpPM, and tumor height from the anal verge (TumorAV). The area under the curve of the FAPS was 0.784 (95% CI: 0.677-0.891). When the cutoff was 4, the sensitivity was 0.833, and the specificity was 0.626. The preoperative pre-planned proximal margin (PpPM) was calculated as follows: PpPM (mm) = 189 (mm) - TumorAV (mm) + 61 × Male (1/0). The proximal margin should be set to be larger than the PpPM to avoid fluorescence abnormalities.

Conclusion: The incidence of fluorescence abnormalities in laparoscopic LAR was 5.4%. If the FAPS is used, the PpPM may be set from the viewpoint of the blood perfusion.

Trial registration: Japanese Clinical Trials Registry: UMIN000032654 ( http://www.umin.ac.jp/ctr/index.htm ).