AUTHOR=Luo Zhe Huang , Qi Wan Ling , Jin Ai Fang , Liao Feng Xiang , Liu Qian , Zeng Qing Yun 

TITLE=The role of 18F-FDG PET/CT in patients with synchronous multiple primary malignant neoplasms occurring at the same time

JOURNAL=Frontiers in Oncology

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2022.1068055

DOI=10.3389/fonc.2022.1068055

ISSN=2234-943X

ABSTRACT=<sec><title>Background</title><p>Synchronous multiple primary malignant neoplasms occurring at the same time (SMPMNS) are not currently uncommon in clinical oncological practice; however, the diagnostic performance of <sup>18</sup>F-fluorodeoxyglucose positron emission tomography/computed tomography (<sup>18</sup>F-FDG PET/CT) for SMPMNS needs further elucidation.</p></sec><sec><title>Purpose</title><p>This study aimed to evaluate the application of <sup>18</sup>F-FDG PET/CT in patients with SMPMNS.</p></sec><sec><title>Materials and methods</title><p>The clinical and imaging data of 37 patients with SMPMNS who had undergone <sup>18</sup>F-FDG PET/CT from October 2010 to December 2020 were retrospectively analyzed. The kappa consistency test was applied to evaluate the consistency of the diagnostic performance between PET/CT and conventional imaging (CI). The sensitivity, specificity, and accuracy of PET/CT and CI in the detection of metastatic lesions were compared.</p></sec><sec><title>Results</title><p>This retrospective diagnostic study included 74 lesions identified in 37 patients with SMPMNS, with 94.6% of patients having double primary tumors. Of the incidences of SMPMNS, 18.9% occurred in the same organ system, with respiratory tumors being the most common type of neoplasm (43.2%) and the lung being the most common primary site (40.5%). The overall survival of SMPMNS patients without metastases was longer than that of those with metastases (<italic>χ</italic><sup>2</sup> = 12.627, <italic>p</italic> = 0.000). The maximum standardized uptake value (SUV<sub>max</sub>), the SUV<sub>max</sub> ratio (larger SUV<sub>max</sub>/smaller SUV<sub>max</sub>), and the difference index of SUV<sub>max</sub> (DISUV<sub>max</sub>) [(larger SUV<sub>max</sub> − smaller SUV<sub>max</sub>)/larger SUV<sub>max</sub>] of the primary lesions ranged from 0.9 to 41.7 (average = 12.3 ± 7.9), from 0.3 to 26.7 (average = 4.4 ± 6.9), and from 0.0% to 96.3% (average = 50.3% ± 29.3%), respectively. With regard to diagnostic accuracy, PET/CT and CI showed poor consistency (<italic>κ</italic> = 0.096, <italic>p</italic> = 0.173). For the diagnosis of primary lesions (diagnosed and misdiagnosed), PET/CT and CI also showed poor consistency (<italic>κ</italic> = 0.277, <italic>p</italic> = 0.000), but the diagnostic performance of PET/CT was better than that of CI. In the diagnosis of metastases, the patient-based sensitivity, specificity, and accuracy of PET/CT were 100.0%, 81.8%, and 89.2%, respectively, while those of CI were 73.3%, 100.0%, 89.2%, respectively. The sensitivity and specificity values were significantly different, with PET/CT having higher sensitivity (<italic>p</italic> = 0.02) and CI showing higher specificity (<italic>p</italic> = 0.02).</p></sec><sec><title>Conclusions</title><p><sup>18</sup>F-FDG PET/CT improves the diagnostic performance for SMPMNS and is a good imaging modality for patients with SMPMNS.</p></sec>