A recent guideline(Yoo et al) says: “Positron emission tomography (PET) is recommended in the M and bilateral nodal staging of patients with advanced stage head and neck squamous cell carcinoma (Stage III, IV) where conventional imaging is equivocal.
•PET is recommended in all patients after conventional imaging and in addition to diagnostic panendoscopy where the primary site is unknown.
•PET is recommended for staging patients with nasopharyngeal carcinoma without clinical evidence of distant disease.”
Many cases of head and neck cancer present with lymph nodes only and in those cases of unknown primary site, PET is generally recommended. Recent literature suggest that PET can be useful for initial staging when the primary is known as well. Kubichek et al found that FDG-PET staging in head and neck cancer has good positive and negative predictive values in determining lymph node status. The maximum SUV of the primary tumor is predictive of overall survival. In 2011, the NCCN Clinical Practice Guidelines in Oncology™ for Head and Neck Cancers have been updated to include PET-CT and CT with contrast as an option for workup in several cancer sites, including oropharynx, hypopharynx, glottic larynx, supraglottic larynx, and nasopharynx. ehad and Neck Society says: “The present generation of PET scanners have superior resolution to the prior units. In the untreated patient, a positive PET study allows identification of tumor, especially in difficult cases where no obvious mass was seen clinically or on either CT or MRI. However, the presence of inflammation in the post operative and/or post irradiated patient can also cause a positive PET study. As a result, PET is now often used in the difficult post treatment patient for its negative predicative value. Thus, a negative PET study has a very high correlation with the absence of tumor.”
nccn.org, Head and Neck, 2011
Yoo J, Walker-Dilks C. PET imaging in head and neck cancer: recommendations. Toronto (ON): Cancer Care Ontario (CCO); 2009 Jan 19. 43 p. (Recommendation report – PET; no. 2). [57 references]
Gregory J Kubicek*, Collin Champ, Shannon Fogh, Fen Wang, Eashwer Reddy, Charles Intenzo, Reginald W Dusing and Mitchell Machtay
FDG-PET staging and importance of lymph node SUV in head and neck cancer Head & Neck Oncology 2010, 2:19