On January 4, Natalia Genere, MD had their review titled “Pressing ‘Pause’ on the Diagnostic Cascade of Incidental Thyroid Nodules in Those with Intercurrent Nonthyroid Cancers,” published in “Clinical Thyroidology.”
The review was meant to further answer the common question of what should be done with incidental thyroid nodules found on FDG-PET scans through reviewing a recent study on the retrospective analyses of 18 FDG-PET/CT thyroid incidentaloma in adults. Genere states, “this study provides further insight into the avoidance of over-diagnosing thyroid cancers in patients receiving FDG-PET/CT imaging for nonthyroid cancers.”
“18-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) is a widely used and effective imaging method for the staging of multiple solid tumor malignancies such as lung cancer, colorectal cancer, and lymphoma.” The method can also identify incidental abnormalities of clinical significance, including incidental thyroid nodules or thyroid incidentalomas (TIs) that can be associated with a risk for malignancy of up to 30%. Using standard biopsy criteria in patients undergoing FDG-PET/CT can lead to overdiagnosis of thyroid cancer.
The study’s data was collected between January 2010 to January 2020, at a Netherlands tertiary cancer center on all patients suspected of or known to have nonthyroid malignancy that underwent FDG-PET/CT imaging. After propensity-score matching among 800 patients, “there was no survival advantage for those who had further evaluation of TIs, as compared with those who did not.” During the observation period of patients with known nonthyroid malignancy, only one patient died of thyroid cancer.
The authors of the study concluded that it is reasonable to defer diagnostic evaluation of most patients with TIs and a concurrent malignancy, and that the initiation of the TI diagnostic cascade or ultrasound surveillance of the thyroid nodule can be implemented for patients with a good prognosis from their primary malignancy.
Genere states, “I wholeheartedly agree that patient comorbidities and prognosis must be considered in decision-making for thyroid FNA biopsy, and that a biopsy should be avoided if definitive surgery is unlikely to impact the prognosis. However, thyroid ultrasound should not necessarily lead to the subsequent testing in the diagnostic cascade; it may be most appropriate to initiate a ‘pause’ upon completion of the ultrasound,” and that “further studies about clinician decision-making can be helpful in informing the appropriate diagnostic steps and intervals of evaluation for patients with FDG-avid TIs.”