The Role of PET/CT Imaging in Lung Cancer

Abstract

Lung cancer presents a high prevalence around the world and constitutes the leading cause of death due to cancer in men and women. Proper staging is essential in order to provide the correct treatment and estimate survival. PET/CT imaging is the method of choice for the staging of lung cancer patients with a better performance than the traditional imaging methods. It allows defining the primary tumor more clearly, separating it from the atelectasis and neighboring fibrotic changes, thus achieving an improved T evaluation while optimizing the target definition for radiotherapy. It presents greater sensibility and specificity than Computed Tomography (CT) when assessing the extra-thoracic and thoracic lymph nodes, modifying the N stage with regard to the traditional study in up to 25% of patients. PET/CT imaging is the method with the best performance for detecting extra-encephalic metastasis and for detecting unexpected lesions in up to 30% of patients. In order to achieve proper encephalic staging, a Magnetic Resonance Imaging scan must be performed or, a CT scan of the brain concomitant to the PET/CT. One to eight percent of lung cancer patients who are subjected to PET/CT imaging present a synchronous secondary extra pulmonary or pulmonary cancer when being diagnosed, with significant prognostic and therapeutic implications. PET/CT imaging has proven to be a valuable tool for survival prognosis with regard to the initial uptake of the tumor and the early response (interim) or final response to chemotherapy, although it is not routinely used for evaluating therapy. The PET/MRI is an emerging hybrid technique with certain advantages, such as less exposure to radiation in comparison to PET/CT and greater contrast resolution of the MRI images. However, its usefulness has not been validated yet for lung cancer patients.