Positron Emission Tomography in the Evaluation of the N0 Neck

Abstract

The presence of cervical lymph node metastasis in patients with head and neck cancer is associated with an unfavorable prognosis. Reports vary as to whether various conventional radiographic studies, such as computed tomography (CT) and magnetic resonance imaging, confer an advantage over physical examination in the patient without clinical findings of cervical metastasis (N0). Positron emission tomography (PET) is a functional imaging modality that has recently been used for head and neck neoplasms. The use of PET in the evaluation of the N0-staged neck in 14 consecutive patients with squamous cell carcinoma (SCC) of the upper aerodigestive tract is reported. Seven patients (50%) undergoing 13 neck dissections had pathologic evidence of disease. PET scans were positive in five patients with pathologically confirmed cervical metastasis. PET scans were negative in seven patients (11 neck dissections) with no pathologic evidence of disease. PET scans were positive for unilateral cervical metastasis in two of three patients with involvement of a single lymph node. PET scans were positive in two of three patients with more than two lymph nodes involved. PET had an accuracy of 100% in the eight patients with SCC of the oral cavity. In patients with oropharyngeal or hypopharyngeal carcinoma PET localized cervical metastasis in two of four patients with neck metastasis. In the patient with an N0-staged neck on clinical examination, PET was found to have an overall sensitivity of 78%, specificity of 100%, positive predictive value of 100%, negative predictive value of 88%, and accuracy of 92%. CT demonstrated sensitivity of 57%, specificity of 90%, positive predictive value of 80%, negative predictive value of 75%, and accuracy of 76%. PET showed a trend in increased accuracy (P = 0.11) over CT. PET appears to be a promising diagnostic aid that may be applied when evaluating the N0-staged neck, especially for SCC of the oral cavity.

Impact of combined 18F-FDG PET/CT in head and neck tumours

“…It is well known that nonspecific uptake in brown fat planes and muscle attachment sites ( Figure 2E) is a common cause of false-positive results (Engel et al, 1996;Kostakoglu et al, 1996;McGuirt et al, 1998). This false-positive feature has a critical impact on nodal staging of head and neck tumours (Helmberger et al, 1996;Myers et al, 1998;Hannah et al, 2002). The possibility of false-positive sites on 18 F-FDG PET alone also holds true in the postsurgical and postradiotherapy neck, where distortion of normal anatomy can further add to the complexity.…”

“…Cervical lymph nodes are the most common site for tumour spread (Mendenhall et al, 1998;Ak et al, 2000), and this is a relatively common clinical presentation (Mendenhall et al, 1998;Ak et al, 2000). The presence or absence of cervical lymphadenopathy is of prognostic significance (Myers et al, 1998).…”

“…The role of 2-[fluorine-18]fluoro-2-deoxy-D-glucose ( 18 F-FDG) positron emission tomography (PET) imaging has previously been evaluated in head and neck tumours, the reported sensitivity and specificity varying between 90 and 96% in primary and treated disease (Myers et al, 1998). Determining the precise location of 18 F-FDG-avid lesions by PET alone can be challenging in these patients, as the test suffers from poor anatomical localisation that might compromise sensitivity (Ak et al, 2000).…”

Gene expression signature predicts lymphatic metastasis in squamous cell carcinoma of the oral cavity

“…Some of the patients without lymph node metastasis at presentation will subsequently manifest metastasis. Since removal of lymph nodes and/or radiation and chemotherapy can reduce emergence of occult metastasis, attempts to predict the patients in this category are made clinically (Kim et al, 1993;Myers et al, 1998). Currently, node-negative patients estimated to have a 20% or greater risk of metastasis often have surgical removal of draining lymph nodes and radiation.…”

Towards a simple, saliva-based test for the detection of oral cancer.

“…It is also impractical to use imaging techniques for cancer screening, since they are time-consuming and expensive. These techniques are typically used for confirmation due to their insensitivity for small lesions [6]. Studies have demonstrated that good positive-predictive values can be achieved by oral cancer tissue staining with toluidine blue [7,8].…”