Is PET superior to MRI in the pretherapeutic evaluation of head and neck squamous cell carcinoma?

OBJECTIVES: This study was designed to compare the effectiveness of positron emission tomography (PET) and magnetic resonance imaging (MRI) in the pretherapeutic staging of squamous cell carcinoma (SCC) of the head and neck.

PATIENTS AND METHODS: The study included 34 consecutive patients (27 males, 7 females; mean age 61 years; range 42 to 82 years) with SCC of the head and neck. All the patients underwent whole body [18F]fluorodeoxyglucose (FDG)-PET and MRI scans for pretherapeutic evaluation. Diagnoses were confirmed by histopathologic examination of endoscopic biopsy specimens.

RESULTS: The sites of the primary tumors were the oropharynx (n=15, 44%), larynx (n=10, 29%), hypopharynx (n=8, 24%), and nasopharynx (n=1, 3%). Surgery was the treatment of choice in 20 patients (59%), including 23 neck dissections. Fourteen patients (41%) were treated with radiochemotherapy. Both PET and MRI were able to detect the primary tumor in 33 cases (97%). In two patients (6%), PET was able to detect distant metastases in the lung and iliac bone, all of which were confirmed by biopsies. Seven neck specimens (30%) showed lymph node metastasis. Sensitivity and specificity rates for detection of lymph node metastasis were 100% and 87.5% for PET, and 85.7% and 87.5% for MRI, respectively.

CONCLUSION: Although PET seems to be superior to MRI in detecting nodal disease and distant metastases, it is still early to recommend it as a primary tool for pretherapeutic evaluation of head and neck cancers due to its limited availability and higher cost.