The role of 18F-Fluorodeoxyglucose PET/CT in restaging patients with small cell lung cancer: A systematic review

Aim 18F-Fluorodeoxyglucose (FDG) PET imaging may play an important role in the restaging of patients with small-cell lung cancer (SCLC), nevertheless, a systematic review of literature was still missing in this setting. The aim of this review was to summarize the evidence on literature regarding the utility of 18F-FDG PET imaging in restaging patients with SCLC. Methods A literature search was performed to retrieve original studies using 18F-FDG PET or 18F-FDG PET/computed tomography (CT) in a minimum of 10 patients with SCLC at restaging. Results The selected literature (17 studies) was discussed in four sections: detection rate, impact on management, prediction of prognosis and evaluation of the response to therapy. According to the literature, PET imaging may result in discordance with conventional imaging, mainly contrast-enhanced CT (ceCT), and detect additional lesions in a certain proportion of cases, leading to upstaging or downstaging. A variable level of disagreement between PET and conventional imaging has been reported also in the evaluation of response to therapy. A positive PET study is associated with shorter survival, especially in the presence of distant metastases. According to some studies, semiquantitative parameters are also inversely associated with overall survival and progression-free survival. Although the retrieved articles proved the utility of 18F-FDG PET imaging in each clinical setting, literature is still limited. Conclusions This review encourages the use of 18F-FDG PET imaging, especially in conjunction with ceCT in recurrent SCLC patients. Further level I evidence is needed to further assess the diagnostic and prognostic capability of 18F-FDG PET/ceCT findings in SCLC.