Near-infrared laparoscopic fluorescence for pelvic side wall delta mapping in patients with rectal cancer- 'PINPOINT' nodal assessment

Abstract

Low rectal cancers metastase lymphatically to the pelvic side wall in addition to cephalad spread alongside the superior rectal/inferior mesenteric arterial axis. Radical surgery in the West has focused resectional intent and effort on the midline en bloc oncological package by Total Mesorectal Excision. While neoadjuvant chemo/radiotherapy (now often administered to patients with radiologically locally advanced cancer) may contribute significant therapeutic effect to the lateral pelvic side walls, many patients with earlier preoperative stage low rectal cancer are offered surgery first (and indeed solely). Furthermore, some of those pretreated may have residual in situ lateral nodal disease and so risk understaging and undertreatment. Routine extended lymphadenectomy is on the otherhand unproven with respect to survival benefit and has likely no added role in the absence of definite (rather than possible) side-wall involvement. Near-infrared fluorescence pelvic side-wall delta mapping, as illustrated here in five patients undergoing abdominoperineal resection for rectal cancer after neoadjuvant therapy, may give the technological capacity to identify tumor site-draining nodes on the pelvic side and the focus the operating surgeon on this potential target for surgical resection (whether by berry picking or nerve sparing clearance) and prompt individualized diagnostic and therapeutic selection.