Utility of Molecular Imaging with 2-Deoxy-2-[Fluorine-18] Fluoro-D-Glucose Positron Emission Tomography (18F-FDG PET) for Small Cell Lung Cancer (SCLC): A Radiation Oncology Perspective

Abstract

Background and Objective: Although accounting for a relatively small proportion of all lung cancers, small cell lung cancer (SCLC) remains to be a global health concern with grim prognosis. Radiotherapy (RT) plays a central role in SCLC management either as a curative or palliative therapeutic strategy. There has been considerable progress in RT of SCLC, thanks to improved imaging techniques leading to accurate target localization for precise delivery of RT. Positron emission tomography (PET) is increasingly used in oncology practice as a non-invasive molecular imaging modality. Methods: Herein, we review the utility of molecular imaging with 2-deoxy-2-[fluorine-18] fluoro-Dglucose PET (18F-FDG PET) for SCLC from a radiation oncology perspective. Results: There has been extensive research on the utility of PET for SCLC in terms of improved staging, restaging, treatment designation, patient selection for curative/palliative intent, target localization, response assessment, detection of residual/recurrent disease, and prediction of treatment outcomes. Conclusion: PET provides useful functional information as a non-invasive molecular imaging modality and may be exploited to improve the management of patients with SCLC. Incorporation of PET/CT in staging of patients with SCLC may aid in optimal treatment allocation for an improved therapeutic ratio. From a radiation oncology perspective, combination of functional and anatomical data provided by integrated PET/CT improves discrimination between atelectasis and tumor, and assists in the designation of RT portals with its high accuracy to detect intrathoracic tumor and nodal disease. Utility of molecular imaging for SCLC should be further investigated in prospective randomized trials to acquire a higher level of evidence for future potential applications of PET.

Impact of 18F-FDG PET/CT in Staging Patients With Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

“…The change of binary SCLC stage may be related to the better diagnostic accuracy of 18 F-FDG PET/CT compared to conventional imaging methods in detecting SCLC metastases in different organs (except for brain metastases), as functional abnormalities detected by 18 F-FDG PET usually precede morphological alterations revealed by conventional imaging methods (5). To this regard, in a previous meta-analysis, the pooled sensitivity, specificity, and positive and negative likelihood ratio (LR+ and LR-) of 18 F-FDG PET or PET/CT in diagnosing ED-SCLC were 97.5% (95%CI, 94.2-99.2%), 98.2% (95% CI, 94.9-99.6%), 19.86 (95% CI, 9.79-40.3), and 0.06 (95% CI, 0.03-0.1), respectively (29).…”

“…Unfortunately, the available data to this regard are not univocal (19,23). The major advantages of 18 F-FDG PET/CT staging in SCLC may lie in avoiding unnecessary toxicity in ED-SCLC and in suggesting the appropriate addition of thoracic radiation therapy in LD-SCLC with potential better patient survival (5). It has been recently demonstrated by a retrospective study in a mixed SCLC patient population performing both 18 F-FDG PET and PET/CT that 18 F-FDG PET staging in patients with SCLC was associated with greater overall survival and lungcancer-specific survival, likely reflecting stage migration and stage-appropriate therapy (17).…”

“…However, if LD-SCLC is suspected, molecular imaging using fluorine-18 fluorodeoxyglucose positron emission tomography ( 18 F-FDG PET) can be performed to assess for distant metastases. In particular, hybrid imaging using 18 F-FDG PET/CT, providing both functional and morphological data, has been demonstrated to be superior to 18 F-FDG PET alone, and it is the current state of art for molecular imaging of lung cancer (5). As SCLC is an aggressive neuroendocrine tumor with increased metabolism and 18 F-FDG is a radiolabeled glucose analog, an increased uptake of this radiopharmaceutical is expected by SCLC lesions (6)(7)(8).…”

Efficacy and Safety of PD-1/PD-L1 Inhibitor Chemotherapy Combined with Lung Cancer Fang No. 1 in Relapsed and Refractory SCLC: A Retrospective Observational Study

“…Compared with non-SCLC, SCLC has biological characteristics such as low degree of differentiation, high degree of malignancy, easy recurrence and metastasis, and poor prognosis. About 70% of SCLC patients are diagnosed at an advanced stage, and the overall 5-year survival rate is less than 10% [ 3 ]. For inoperable patients, the objective response rate of first-line platinum-containing doublet chemotherapy is higher, but more than 80% of patients will relapse within 2 years, and the median survival (OS) after relapse is only 4-5 months [ 4 ].…”

Assessment of the role of multimodality imaging for treatment volume definition of intracranial ependymal tumors: An original article

“…In this regard, accurate treatment volume determination is an indispensable aspect of contemporary irradiation strategies. There has been signifi cant progress with excellent improvements regarding radiation oncology practice by introduction of modernized treatment equipment, contemporary and adaptive irradiation strategies [16][17][18][19][20]. With regard to radiotherapeutic management of intracranial ependymomas, accumulating data suggest promising treatment results [3][4][5][6][7][8][9][10][11][12][13][14][15].…”