The future in diagnosis and staging of lung cancer: positron emission tomography

Since its introduction in 1974, positron emission tomography (PET) has gained widespread use, especially in diagnosis and staging of lung cancer. In this respect, (18)F-fluorodeoxyglucose (FDG) is by far the most used PET tracer exploiting the increased glucose uptake and metabolism in malignant cells. A large number of studies have suggested that addition of FDG-PET to conventional workup can improve diagnosis and staging in patients with non-small cell lung cancer (NSCLC). In meta-analysis, the sensitivity and specificity of PET in diagnosing single pulmonary nodules and masses is found to be 96 and 78%, respectively. In mediastinal staging, the sensitivity and specificity of PET is estimated to be 83 and 92%. In order to achieve high diagnostic values from PET, it is necessary to pay attention to a number of pitfalls, e.g., the uptake of FDG by inflammatory cells causing false-positive results, as well as size and histology of the tumour in order to avoid false-negative results. In 2001, the first integrated PET/computed tomography (CT) was installed, and since then, the use of this modality has expanded steadily, thereby decreasing examination time and overcoming the lack of anatomical details on PET. Recently, PET and PET/CT have become increasingly integrated in therapy planning and evaluation: response evaluation during and after chemotherapy, restaging after neoadjuvant therapy, planning of radiotherapy and detection of recurrent disease are all examples of emerging indications for PET and PET/CT in managing patients with lung cancer.