ORIGINAL ARTICLE   

The Quarterly Journal of Nuclear Medicine and Molecular Imaging 2020 September;64(3):291-8

DOI: 10.23736/S1824-4785.19.03140-6

Copyright © 2019 EDIZIONI MINERVA MEDICA

language: English

Is 18F-fluorodeoxyglucose positron emission tomography/computed tomography useful to discriminate metachronous lung cancer from metastasis in patients with oncological history?

Silvia TARALLI ¹, Valentina SCOLOZZI ^{1, 2}, Elizabeth K. TRIUMBARI ^{1, 2}, Francesco CARLEO ³, Marco DI MARTINO ³, Alessia R. DE MASSIMI ³, Sara RICCIARDI ⁴, Giuseppe CARDILLO ³, Maria L. CALCAGNI ^{1, 2} ✉

¹ UOC di Medicina Nucleare, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy; ² Istituto di Medicina Nucleare, Università Cattolica del Sacro Cuore, Rome, Italy; ³ Unit of Thoracic Surgery, San Camillo Forlanini Hospital, Rome, Italy; ⁴ Unit of Thoracic Surgery, University Hospital of Pisa, Pisa, Italy

BACKGROUND: Solitary pulmonary nodules detected during follow-up in patients with previous cancer history have a high probability of malignancy being either a metachronous lung cancer or a metastasis. This distinction represents a crucial issue in the perspective of “personalized medicine,” implying different treatments and prognosis. Aim: to evaluate the role of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in distinguishing whether solitary pulmonary nodules are metachronous cancers or metastases and the relationship between the nodule’s characteristics and their nature.
METHODS: From a single-institution database, we retrospectively selected all patients with a previous cancer history who performed 18F-FDG PET/CT to evaluate pulmonary nodules detected during follow-up, ranging from 5 mm to 40 mm, and histologically diagnosed as malignant.
RESULTS: Between September 2009 and August 2017, 127 patients (80 males; mean age=70.2±8.5years) with 127 malignant nodules were included: 103/127 (81%) metachronous cancers, 24/127 (19%) metastases. In both groups, PET/CT provided good and equivalent detection rate of malignancy (81% vs. 83%). No differences between metachronous cancers and metastases were found in: patient’s age (70.3±8.1 years vs. 69.5±9.7years), gender (males=63.1% vs. 62.5%), interval between previous cancer diagnosis and nodules’ detection (median time=4years vs. 4.5years), location (right-lung=55% vs. 54%; upper-lobes=64% vs. 67%; central-site=31% vs. 25%), size (median size=17mm vs. 19.5mm), 18F-FDG standardized uptake value (median SUVmax=5.2 vs. 5.9).
CONCLUSIONS: In oncological patients, despite its high detection rate, 18F-FDG PET/CT, as well as any other clinico-anatomical features, cannot distinguish whether a malignant solitary pulmonary nodule is a metachronous lung cancer or a metastasis, supporting the need of histological differential diagnosis.

KEY WORDS: Solitary pulmonary nodule; Fluorodeoxyglucose F18; Positron emission tomography computed tomography; Neoplasm metastasis