title: 18F-fluorodeoxyglucose positron emission tomographic scan in solid-type p-stage-I pulmonary adenocarcinomas: what can produce false-negative results?
abstract: False-negative (FN) uptake of 18F-fluorodeoxyglucose (FDG) can be divided into those cases related to technological limitations of positron emission tomography (PET) and those related to inherent properties of neoplasms. Our goal was to clarify possible factors causing FN PET results in patients with solid-type pulmonary adenocarcinomas (PAs).
  
  
  
  From January 2007 to December 2014, of the 255 patients with p-stage-1 non-small-cell lung cancer observed and treated (surgically) in our institution, we retrospectively reviewed the PET/computed tomography (CT) records, the clinical information, the preoperative thin-section CT images, and the pathological features [classified by the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) subtyping criteria] of 94 consecutive solid-type p-stage-1 PAs. Univariable and multivariable logistic analyses were used to identify and weigh the independent predictors of the PET findings using the following variables: body weight, blood glucose level, tumour size, tumour location, and histological classification.
  
  
  
  There were 58 men and 36 women (mean age = 68.7 ± 8.9 years, range 42-85). Considering the maximum standardized uptake value (SUVmax) ≥ 2.5 as a 'PET-positive' result, 77 lesions (81.9%) proved PET positive and 17 lesions (18.1%), PET negative (with SUVmax < 2.5). Overall, the median SUVmax value was 5.7 [interquartile range (IQR) 2.8-10.3]. Higher SUVmax values ( P  < 0.001) were observed in those PAs larger than 2 cm in their major axis (median SUVmax = 9.0; IQR 4.6-14.6); in PAs < 2 cm, the median SUVmax was 4.1; IQR 2.2-5.9. When clustering the cohort in two histological classes (class A, colloid/mucinous/lepidic versus class B, micropapillary/solid/acinar/papillary), the radiometabolic patterns were significantly different (median SUVmax = 2.8; IQR 1.7-4.9 in class A vs median = 7.4 IQR 4.5-13.9 in class B, P  <   0.001). Significant PET FN rates were reported in (i) PAs measuring < 2 cm in their major axis (27.9%), (ii) lesions located in the lower zones of the lung (31.0%), and (iii) class A tumours (37.5%). In the multivariable logistic analysis, histological type (IASLC/ATS/ERS aggregated clusters) proved to be the only independent relevant factor for determining whether PET results were negative or positive (OR:7.23, 95% CI: 2.05-25.43, P  =   0.002).
  
  
  
  The IASLC/ATS/ERS pattern significantly influences FDG uptake in solid-type p-stage-1 PAs. The fact that colloid/mucinous/lepidic adenocarcinomas have a notable tendency to produce negative findings on PET scans warrants particular attention.
authors.affiliation: Unit of Thoracic Surgery, Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy.
authors.forename: Filippo
authors.initials: F
authors.lastname: Lococo
authors.affiliation: Unit of Thoracic Surgery, Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Galeone
authors.affiliation: Department of Infrastructure Research and Statistics, Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy.
authors.forename: Debora
authors.initials: D
authors.lastname: Formisano
authors.affiliation: Unit of Pathology, Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Bellafiore
authors.affiliation: Unit of Nuclear Medicine, Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy.
authors.forename: Angelina
authors.initials: A
authors.lastname: Filice
authors.affiliation: Unit of Nuclear Medicine, Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy.
authors.forename: Tartaglione
authors.initials: T
authors.lastname: Annunziata
authors.affiliation: Clinical Governance, Fondazione Policlinico Agostino Gemelli, Università Cattolica del Sacro Cuore, Rome, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Cesario
authors.affiliation: Unit of Thoracic Surgery, Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy.
authors.forename: Cristian
authors.initials: C
authors.lastname: Rapicetta
authors.affiliation: Medical Physics Unit, Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Fioroni
authors.affiliation: Unit of Thoracic Surgery, Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Ricchetti
authors.affiliation: Unit of Thoracic Surgery, Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Paci
mesh_terms: D000230:Adenocarcinoma / Q000097:blood / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D000077192:Adenocarcinoma of Lung; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000032:analysis; D001835:Body Weight; D005188:False Negative Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods; D019275:Radiopharmaceuticals; D012189:Retrospective Studies
chemical_list: D001786:Blood Glucose; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: FDG uptake ; IASLC/ATS/ERS classification ; NSCLC; PET/CT ; false-negative result ; pulmonary adenocarcinoma 