Second window indocyanine green for oropharyngeal tumours: A case series and comparison of near‐infrared camera systems

Abstract

Negative margin status is the most important prognosticator in the surgical treatment of oropharyngeal squamous cell carcinoma (OPSCC), but can be challenging to achieve with tumours in poorly visualised regions. 1 This can be magnified in transoral robotic surgery (TORS) due to limited haptic feedback and anatomic constraints preventing palpation of the tumour during resection. Positive margin rates have improved with increased experience with TORS, but remain high at nearly 16% nationally 2 and 26% at low-volume centres. 3,4 The ability to obtain favourable oncologic outcomes with TORS on even locally advanced tumours has been demonstrated, 5,6 but avoidance of postoperative adjuvant therapy is dependent on ability to obtain negative margins amongst other factors. 7,8 Fluorescence molecular imaging (FMI) using near-infrared (NIR) fluorophores has been increasingly used to augment margin definition and residual tumour detection in vivo for achieving tumour-free margins.The NIR dye indocyanine green (ICG), routinely used for FMI, accumulates in areas of disrupted, permeable endothelium (i.e., neoplastic tissue) via the enhanced-permeability-and-retention effect. 9 Additionally, ICG accumulates within tumours due to poorly developed tumoural lymphatics.Recently, TORS has advanced the surgical treatment of OPCSCC. 10 Unfortunately, prior studies found that ICG failed to identify head and neck lesions and achieve tumour-free margins during TORS. 11 Our group previously demonstrated that NIR imaging of ICG injected 24 h pre-operatively, a novel technique called Second Window ICG (SWIG), with the VisionSense TM Iridium platform, could be used for intraoperative identification of head and neck lesions and regional metastasis. 12 The current study's objective was to compare a surgical robot-integrated NIR system to a dedicated NIR imaging platform for intraoperative imaging with SWIG.

Role of transoral robotic surgery in the salvage setting: pitfalls and challenges

“…Improve visualization techniques, in combination with TORS approaches, allow for better identification of tumors. While indocyanine green fluorescence has been shown to improve margin status in head and neck cancers [55] , this has proven difficult to utilize during TORS surgery. A novel technique utilizing indocyanine green in combination with the existing da Vinci robotic near-infrared system has shown promising results [56] .…”