Fluorescence-guided surgery using cetuximab-800CW in patients with penile carcinoma

OBJECTIVE: To investigate the feasibility of fluorescence molecular imaging (FMI), using cetuximab-800CW, as an intraoperative tool to determine surgical margins in penile squamous cell carcinoma (PSCC).

PATIENTS AND METHODS: A total of 11 patients with PSCC received 75 mg cetuximab followed by 15 mg cetuximab-800CW 2 days before surgery. FMI of the whole excision specimen and tissue slices was performed. Fluorescence visualisation was correlated to histopathology. Based on tumour and healthy tissue regions of interest, mean fluorescence intensity was calculated for each individual patient.

RESULTS: Significant differences between tumour and healthy mean fluorescence intensity were found with tumour-to-background ratios of a median (IQR) of 1.51 (0.99) and a mean (SD) of 1.51 (0.32) in the excision specimen and tissue slices, respectively. One patient showed a high relative fluorescence intensity with a signal-to-background ratio of 1.79, corresponding to a tumour-positive margin on fresh frozen sectioning.

CONCLUSION: In this Phase I study we showed that cetuximab-800CW seems suitable to discriminate PSCC from background tissue. The tracer was well tolerated, and no false positive spots were seen.