18F-FDG-PET reduces the number of direct laryngoscopies in patients with suspected recurrent laryngeal carcinoma after radiotherapy

Objectives The goal of this study was to examine 18F-FDG-PET as first-line diagnostic investigation in patients suspected of recurrent laryngeal carcinoma after radiotherapy.

Methods 150 patients suspected of recurrent T2-4 laryngeal carcinoma after radiotherapy were randomised to direct laryngoscopy (CWU: conventional workup strategy) or to 18F-FDG-PET only followed by direct laryngoscopy if PET was assessed ‘positive’ or ‘equivocal’ (PWU: PET based workup strategy). Primary endpoint was the number of indications for direct laryngoscopies classified as unnecessary based on absence of recurrence, both on laryngoscopy and on six months follow up. Safety endpoints comprised resectability and surgical margins.

Results Tumor recurrence was similar in both groups: 45 patients (30%; 21/74 CWU, 24/76 PWU) within six months. In 53 patients in the CWU arm (72%, 95%CI: 60-81) unnecessary direct laryngoscopies were performed compared to 22 in the PWU arm (29%, 95%CI: 19-40) (p<0.0001). The percentage of salvage laryngectomies (resectability) and positive surgical margins were similar between CWU and PWU (81%, 63% respectively, p=0.17, and 29%, 7%, respectively, p=0.20).

Conclusions In patients with suspected laryngeal carcinoma after radiotherapy, PET as first diagnostic procedure can reduce the need for direct laryngoscopy by more than 50% without jeopardizing quality of treatment.