Detection of distant metastatic disease at initial staging is crucial because it will change prognosis and typically convert the management strategy toward more systemic options. Radiography Chest CXR is not considered the imaging modality of choice for evaluation of pulmonary metastatic disease in suspected or diagnosed nasopharynx cancer or EBV-associated unknown primary of the head and neck. Chest CT is far more sensitive in detecting pulmonary metastatic disease compared to radiography [15], with the sensitivity of CXR to detect pulmonary metastatic disease reported to be as low as 28% compared to chest CT [11]. The low sensitivity may in part be due to the small size of pulmonary nodules at presentation or peripheral location, in which CXR tends to be less reliable [11]. The use of CXR for detection of metastases has not been shown to improve prognosis, because pulmonary metastatic disease detected on CXR tends to be diagnosed at a late stage when it is not as amenable to treatment [18]. CT Chest With IV Contrast CT chest with IV contrast can accurately identify pulmonary metastases and be used to detect thoracic nodal and skeletal metastases to ribs or vertebrae. NPC has a relatively high rate of distant metastases with the lung being the second most common site of distant disease after osseous metastases. Although FDG-PET/CT is preferred for the staging of advanced stage NPC because it allows for simultaneous detection of metastatic disease outside the thorax, CT chest may be considered for screening of pulmonary metastatic disease. CT chest confers superior spatial localization and contrast resolution compared to radiography, allowing for the detection of small pulmonary nodules [15]. CT chest may also be useful in patients with NPC associated with smoking and alcohol intake, given the risk for synchronous lung cancer.
Staging and Post Therapy Assessment of Head and Neck Cancer. Detection of distant metastatic disease at initial staging is crucial because it will change prognosis and typically convert the management strategy toward more systemic options. Radiography Chest CXR is not considered the imaging modality of choice for evaluation of pulmonary metastatic disease in suspected or diagnosed nasopharynx cancer or EBV-associated unknown primary of the head and neck. Chest CT is far more sensitive in detecting pulmonary metastatic disease compared to radiography [15], with the sensitivity of CXR to detect pulmonary metastatic disease reported to be as low as 28% compared to chest CT [11]. The low sensitivity may in part be due to the small size of pulmonary nodules at presentation or peripheral location, in which CXR tends to be less reliable [11]. The use of CXR for detection of metastases has not been shown to improve prognosis, because pulmonary metastatic disease detected on CXR tends to be diagnosed at a late stage when it is not as amenable to treatment [18]. CT Chest With IV Contrast CT chest with IV contrast can accurately identify pulmonary metastases and be used to detect thoracic nodal and skeletal metastases to ribs or vertebrae. NPC has a relatively high rate of distant metastases with the lung being the second most common site of distant disease after osseous metastases. Although FDG-PET/CT is preferred for the staging of advanced stage NPC because it allows for simultaneous detection of metastatic disease outside the thorax, CT chest may be considered for screening of pulmonary metastatic disease. CT chest confers superior spatial localization and contrast resolution compared to radiography, allowing for the detection of small pulmonary nodules [15]. CT chest may also be useful in patients with NPC associated with smoking and alcohol intake, given the risk for synchronous lung cancer.