Interim Phase II Results Using Panitumumab-IRDye800CW During Transoral Robotic Surgery in Patients with Oropharyngeal Cancer

Abstract Purpose: The incidence of oropharyngeal squamous cell carcinoma (OPSCC) has continually increased during the past several decades. Using transoral robotic surgery (TORS) significantly improves functional outcomes relative to open surgery for OPSCC. However, TORS limits tactile feedback, which is often the most important element of cancer surgery. Fluorescence guided surgery (FGS) strategies to aid surgeon assessment of malignancy for resection are in various phases of clinical research but have the greatest potential impact for improving patient care when the surgeon has limited tactile feedback, such as during TORS. Here, we assessed the feasibility of intraoperative fluorescence imaging using panitumumab-IRDye800CW (PAN800) during TORS in OPSCC patients. Patients and Methods: 12 consecutive patients with OPSCC were enrolled as part of a non-randomized, prospective, phase II FGS clinical trial using PAN800. TORS was performed with an integrated robot camera for surgeon assessment of fluorescence. Intraoperative and ex vivo fluorescence signals in tumors and normal tissue were quantified and correlated with histopathology. Results: Intraoperative robot fluorescence views delineated OPSCC from normal tissue throughout the TORS procedure (10.7 mean tumor-to-background ratio), including in tumors with low expression of the molecular target. Tumor-specific fluorescence was consistent with surgeon-defined tumor borders requiring resection. Intraoperative robot fluorescence imaging revealed an OPSCC fragment initially overlooked during TORS based on brightfield views, further substantiating the clinical benefit of this FGS approach. Conclusions: Results from this OPSCC patient cohort support further clinical assessment of FGS during TORS to aid resection of solid tumors.