Incidentalomas of the prostate detected by 18-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography

Abstract

Introduction: Prostate incidentalomas are prostatic lesions suspicious for cancer discovered by imaging patients without a known history of prostatic cancer (CaP) for other reasons. 18-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG PET) is used to diagnose, stage and assess response to treatment for numerous cancers, but it is not routinely used for CaP. We aimed to determine the rate of detection of prostate incidentalomas in patients undergoing FDG PET and to evaluate the natural history of these lesions.
 Methods: A retrospective review was conducted of all FDG PET scans performed between 2005 and 2017 at a single institution. Patients were selected who had prostatic uptake without a history of prostate cancer. Clinical data were collected from electronic medical records to determine how the prostate incidentalomas were further evaluated and define the rate of malignancy.
 Results: A prostate incidentaloma was identified in 309 (1.0%) of 31 019 FDG PET scans performed on men. A prostate-specific antigen (PSA) test was obtained in 40.1% of patients within six months of prostate incidentaloma detection. Six patients underwent a multiparametric magnetic resonance imaging (MRI) of the prostate, which identified CaP in one case. Overall, CaP was diagnosed in 33 cases, representing 10.7% of the prostate incidentalomas and 0.1% of the scanned patients. CaP was intermediate- or high-risk in 27 (8.7%) of the prostate incidentalomas.
 Conclusions: Incidental lesions detected in the prostate by FDG PET may represent clinically significant CaP. Referral to a urologist for further evaluation should be considered if the patient is otherwise in reasonable health.

Prevalence and Clinical Significance of Incidental Focal ¹⁸F-FDG Uptake in Colon on PET/CT Imaging

“…In imaging studies, an incidental finding, which is commonly named as “incidentaloma,” is a lesion which is detected serendipitously and is of indeterminate clinical significance. 18 Fluorine-fluorodeoxyglucose ( 18 F-FDG) positron emission tomography/computed tomography (PET/CT) is increasingly being used as an imaging modality in oncology and this has led to an increasing number of focal 18 F-FDG-avid lesions in several organs including the thyroid gland, adrenal gland gastrointestinal tract, pituitary gland, prostate gland ( 1 , 2 , 3 , 4 , 5 ). Although identification of some of these findings may provide a chance to treat a secondary primary malignancy, in many cases, further studies done for exploration of these lesions might cause unnecessary anxiety in patients, complications from additional medical interventions and economic burden ( 6 , 7 ).…”

Dual-Tracer Positron-Emission Tomography Using Prostate-Specific Membrane Antigen and Fluorodeoxyglucose for Staging of Prostate Cancer: A Systematic Review

“…Biomarker-focused research supports this hypothesis, with a retrospective analysis in 66 patients referred for RLT, of which 41 patients (62%) had at least one PSMA-negative FDG-positive lesion and demonstrated higher levels of neuron-specific enolase, a neuroendocrine marker [ 52 ]. Furthermore, neuroendocrine PCa has a more aggressive course and thereby an expectation of increased anaerobic glycolysis with consequent FDG avidity [ 24 ]. This is in keeping with existing evidence on divergent clonal evolution of CRPCa and the “genomic overlap” between conventional adenocarcinoma and neuroendocrine PCa in the development of castration resistance [ 53 ].…”

“…Increasing use of FDG PET to aid patient selection for RLT and other therapies in mCRPCa has provided insight into tumour heterogeneity and benefits of dual-tracer PET imaging [ 22 , 23 ]. Discordant findings have been attributed to the increased anaerobic glycolysis detected by FDG PET in patients with more aggressive histological types [ 24 ]. Whilst the use of PSMA and FDG PET imaging in PCa has been examined individually, the potential diagnostic impact for individual patients to undergo dual-tracer PET imaging remains unclear.…”

Prostate incidentaloma on 18F-fluorodeoxyglucose positron emission tomography: Diagnostic value of volumetric positron emission tomography parameters

“…Although histopathologic examination is the gold standard in distinguishing benign PI from malignant PI, this procedure is often unnecessary due to the indolent course of prostate cancer and the clinical condition caused by the patients' primary malignancies and other accompanying diseases. However, early diagnosis and treatment of prostate cancer as a second primary in patients with long life expectancy gains importance as prognostic [4]. In most studies that included SUVmax values in PI, the malignant group's average SUVmax values were higher than in the benign group [6,8,10,11,12,13,14,19].…”

“…Incidental focal FDG uptake that is not related to the disease primarily examined in any organ in PET/CT, is called incidentaloma. These lesions may be physiologic or associated with benign pathologies, as well as indicative of pathologies such as second primary malignancy [4]. Although the incidence of prostate incidentaloma (PI) is a small percentage (1.8 %), it affects a large male patient population, given the ever-increasing annual 18F-FDG PET/CT numbers [5].…”