An assessment of F-FDG PET/CT for thoracic screening and risk stratification of pulmonary nodules in multiple endocrine neoplasia type 1.

CONTEXT

Bronchopulmonary neuroendocrine tumours (bpNETs) and thymic carcinoid (ThC) are features of multiple endocrine neoplasia type 1 (MEN 1), and surveillance guidelines recommend periodic thoracic imaging. The optimal thoracic imaging modality and screening frequency remain uncertain as does the prognosis of small lung nodules when identified.

OBJECTIVES

To evaluate fluorodeoxyglucose positron emission tomography/computed tomography ( F-FDG PET/CT) for identification and prognostic assessment of thoracic lesions in MEN 1.

DESIGN

Retrospective observational study.

SETTING AND PARTICIPANTS

Fifty consecutive MEN 1 patients undergoing screening with F-FDG PET/CT at a tertiary referral hospital between July 2011 and December 2016.

INTERVENTIONS

F-FDG PET/CT.

OUTCOME MEASURES

Pulmonary and thymic lesion prevalence, size, functional characteristics and behaviour.

RESULTS

Thirteen patients (26.0%) exhibited pulmonary nodules with multiple nodules identified in nine (18.0%). An asymptomatic 31 mm FDG-avid ThC was identified in one patient (2%). Of the 13 patients with pulmonary nodules, four (8.0%) exhibited 13 FDG-avid nodules (mean size 10.1 ± 9.1 mm), and nine (18.0%) demonstrated 26 FDG nonavid nodules (mean size 6.9 ± 5.8 mm). All FDG-avid lesions increased in size vs 11 (42.3%) FDG nonavid lesions (P = .0004). For FDG-avid and nonavid nodules, the median doubling time was 24.2 months (IQR 11.4-40.7) and 48.6 months (IQR 37.0-72.2), respectively. Nodule resection was undertaken in two patients, typical bronchial carcinoid diagnosed in one (FDG nonavid) and metastatic renal cell carcinoma in the second (FDG avid).

CONCLUSION

Thoracic imaging with F-FDG PET/CT effectively identifies pulmonary nodules and ThC. FDG-avid pulmonary lesions are significantly more likely to progress than nonavid lesions.