Morphologic Investigations in Head and Neck Cancer

Abstract

Head and neck cancer (HNC) is the fifth most common cancer worldwide and is traditionally associated with high morbidity and mortality. Patients with head and neck squamous cell cancer require a careful evaluation and a multidisciplinary team approach to determine optimal management. Treatment planning depends on TNM staging, which is evaluated with physical examination, endoscopies, and cross-sectional imaging. CT and MR imaging form the main stays of cross-sectional imaging and is extensively utilized in characterizing and staging of malignant tumors involving the head and neck which is critical for the selection of appropriate therapeutic regimens. The goal of imaging in patients with HNC are to establish tumor extent and size, to assess nodal disease, for possible perineural tumor spread, to distinguish recurrent tumor from posttreatment changes, and to monitor the result and response of treatment. Cross-sectional imaging supplements and compliments the physical examination by delineating the complex anatomic and pathological changes of the neck. CT and MRI complement each other; certain conditions are better studied with one than the other. Various strengths and weaknesses of each modality should be carefully considered when selecting them for tumor assessment and follow up. Certain newer techniques, such as CT and MR perfusion, MR spectroscopy, facilitate the evaluation of functional parameters in oncologic patients, such as tissue perfusion, which can integrate the morphologic and metabolic information derived from conventional techniques and have the potential to identify the characteristics that could indicate malignant progression. Recently, functional imaging with 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) was introduced and found to be superior to conventional imaging work-ups in the evaluation of patients with head and neck malignancies. It improves the detection of occult cervical lymphatic disease, distant metastasis, and assists in localization of unknown primary carcinoma of head and neck region or a synchronous second tumor. Combined PET/CT scanners have improved anatomic localization of HNC, incorporating the anatomic accuracy of CT with functional data of 18FDG-PET. From methodological development, these morphologic investigations are making the critical transition to preclinical and clinical validating methods and eventually to widespread clinical tools.