F-18 FDG PET-CT fusion in radiotherapy treatment planning for head and neck cancer

BACKGROUND: The fusion of fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) with CT scans has been shown to improve diagnostic accuracy and staging in non-small cell lung cancer. We report on the influence of PET-CT fusion on the management of patients with head and neck cancer. METHODS: Thirty-six patients with intact primary head and neck cancers treated with radiation therapy (RT) received PET-CT as part of treatment planning. Workup before PET-CT included a contrast-enhanced CT scan of the head and neck and chest X-ray; patients with nasopharyngeal and paranasal sinus primary tumors also underwent MRI. RESULTS: Changes in TNM score and American Joint Committee on Cancer stage occurred in 13 patients (36%) and five patients (14%), respectively, based on PET-CT. RT volume and dose were altered in five patients (14%) and four patients (11%), respectively. Five patients initially were seen with carcinoma of unknown primary, and PET-CT confirmed oropharyngeal primary tumors in two. PET-CT data also detected a synchronous lung cancer in one patient. CONCLUSION: PET-CT fusion may have a significant impact on staging and determination of RT treatment volume and dose.