Prevalence and outcomes of incidental imaging findings: umbrella review

Abstract

ObjectiveTo provide an overview of the evidence on prevalence and outcomes of incidental imaging findings. DeSiGNUmbrella review of systematic reviews. Data SOurceSSearches of MEDLINE, EMBASE up to August 2017; screening of references in included papers. eliGibility criteria Criteria included systematic reviews and meta-analyses of observational studies that gave a prevalence of incidental abnormalities ("incidentalomas"). An incidental imaging finding was defined as an imaging abnormality in a healthy, asymptomatic patient or an imaging abnormality in a symptomatic patient, where the abnormality was not apparently related to the patient's symptoms. Primary studies that measured the prevalence of incidentalomas in patients with a history of malignancy were also considered in sensitivity analyses. reSultS 20 systematic reviews (240 primary studies) were identified from 7098 references from the database search. Fifteen systematic reviews provided data to quantify the prevalence of incidentalomas, whereas 18 provided data to quantify the outcomes of incidentalomas (13 provided both). The prevalence of incidentalomas varied substantially between imaging tests; it was less than 5% for chest computed tomography for incidental pulmonary embolism in patients with and without cancer and whole body positron emission tomography (PET) or PET/computed tomography (for patients with and without cancer). Conversely, incidentalomas occurred in more than a third of images in cardiac magnetic resonance imaging (MRI), chest computed tomography (for incidentalomas of thorax, abdomen, spine, or heart), and computed tomography colonoscopy (for extracolonic incidentalomas). Intermediate rates occurred with MRI of the spine (22%) and brain (22%). The rate of malignancy in incidentalomas varied substantially between organs; the prevalence of malignancy was less than 5% in incidentalomas of the brain, parotid, and adrenal gland. Extra-colonic, prostatic, and colonic incidentalomas were malignant between 10% and 20% of the time, whereas renal, thyroid, and ovarian incidentalomas were malignant around a quarter of the time. Breast incidentalomas had the highest percentage of malignancy (42%, 95% confidence interval 31% to 54%). Many assessments had high between-study heterogeneity (15 of 20 metaanalyses with I 2 >50%).cONcluSiONS There is large variability across different imaging techniques both in the prevalence of incidentalomas and in the prevalence of malignancy for specific organs. This umbrella review will aid clinicians and patients weigh up the pros and cons of requesting imaging scans and will help with management decisions after an incidentaloma diagnosis. Our results can underpin the creation of guidelines to assist these decisions.

Incidental imaging findings on oral radiology

“…O’Sullivan and colleagues emphasise the importance of incidental imaging findings 1. We agree with their conclusions: the high prevalence of incidental imaging findings; that clinicians should weigh up the benefits and risks before ordering an imaging test; and the need for precise guidelines about management 1…”

S‐100B as an extra selection tool for FDG PET/CT scanning in follow‐up of AJCC stage III melanoma patients

“…Based on the scheduled outpatient visits, with corresponding FDG PET/CT scans (€913) and S-100B samples (€109), the follow-up costs for 100 patients using the TRIM protocol would be €408.800 compared to the cost of €88.050 in our current study. Compared to the UMCG protocol applied in our present study, the standard scanning proposed in the TRIM study might lead to earlier detection of metastases, but would also greatly increase melanoma follow-up costs and the radiation burden.Moreover, the additional scans would lead to incidental findings not contributing to melanoma treatment or disease-related survival 31. The current study protocol could reduce FDG PET/CT scans in asymptomatic melanoma patients, thereby reducing their radiation exposure and the total follow-up costs compared to a standard scanning protocol.…”

Incidental findings on imaging

“…As O’Sullivan and colleagues show in a linked article (doi:10.1136/bmj.k2387),1 unexpected anomalies discovered during imaging are common. However, they are also problematic 234.…”

“…If we are to first do no harm, we should change our mindset and start thinking of unexpected anomalies as side effects of medical imaging, and seek fully informed consent before going ahead 11. To aid this shared decision making,4 O’Sullivan and colleagues are to be commended for their scholarship in completing a Herculean analysis of an entire literature on the prevalence of these “incidentalomas.”1…”

“…The authors defined incidentaloma as “an imaging abnormality in a healthy, asymptomatic patient or an imaging abnormality in a symptomatic patient, where the abnormality is not apparently related to the patient’s symptoms.”1 In the context of radiological diagnostics perhaps a more useful definition of incidentalomas is “those findings that are discovered by chance which can potentially affect the health of an individual.”7 This would include other potentially harmful lesions such as large cerebral aneurysms in addition to the possible malignancies reported by O’Sullivan and colleagues. A further benefit would be that many normal variants, physiological features, or clinically irrelevant lesions would be excluded from the prevalence.…”