The impact of post-radioiodine therapy SPECT/CT on early risk stratification in differentiated thyroid cancer; a bi-institutional study

Abstract

ObjectiveSPECT/CT has numerous advantages over planar and traditional SPECT images. The aim of this study was to evaluate the role of post-radioiodine therapy SPECT/CT of patients with differentiated thyroid cancer (DTC) in early risk classification and in prediction of late prognosis.Patients and methods323 consecutive patients were investigated after their first radioiodine treatment (1100–3700 MBq). Both whole body scan and SPECT/CT images of the head, neck, chest and abdomen regions were taken 4–6 days after radioiodine therapy. Patients were re-evaluated 9–12 months later as well as at the end of follow up (median 37 months).ResultsPost-radioiodine therapy SPECT/CT showed metastases in 22% of patients. Lymph node, lung and bone metastases were detected in 61, 13 and 5 patients, respectively, resulting in early reclassification of 115 cases (36%). No evidence of disease was found in 251 cases at 9–12 months after radioiodine treatment and 269 patients at the end of follow-up. To predict residual disease at the end of follow-up, the sensitivities, specificities and diagnostic accuracies of the current risk classification systems and SPECT/CT were: ATA: 77%, 47% and 53%; ETA: 70%, 62% and 64%; SPECT/CT: 61%, 88% and 83%, respectively. There was no difference between cohorts of the two institutions when data were analyzed separately.ConclusionsBased on our bi-institutional experience, the accuracy of post-radioiodine SPECT/CT outweighs that of the currently used ATA and ETA risk classification systems in the prediction of long-term outcome of DTC.

The Diagnostic Usefulness of 131I-SPECT/CT at Both Radioiodine Ablation and during Long-Term Follow-Up in Patients Thyroidectomized for Differentiated Thyroid Carcinoma: Analysis of Tissue Risk Factors Ascertained at Surgery and Correlated with Metastasis Appearance

“…The favorable results of SPECT/CT and the incremental benefit over WBS obtained in this study agree with the data reported in previous studies in both pre [3,38,39] and post [40][41][42][43][44][45]56,57] ablation phases as well as during long-term follow-up [9,10,[46][47][48][49][50], including in the latter cases data obtained with routine use of the procedure [9,10,47].…”

Evaluation of Diagnostic Value of SPECT/CT Imaging in Post-radioiodine Therapy in Thyroid Cancer

“…The current findings are similar to other studies where risk classification was changed in 6.4%, 25% and 35.6% of patients, respectively, after SPECT/CT and change in TNM stage was seen in 6.1%, 25.9% and 21% of patients. 2 , 3 , 16 , 20 , 26 Similarly, change in therapeutic plan was observed in 2.0%, 24% and 19.4% of patients after SPECT/CT. 3 , 7 , 19 This variability in results may be explained due to differences in the qualitative assessment of image findings, patient population, age, histopathologies and variation in study protocols.…”

Pre-Treatment and Post-Treatment I-131 Imaging in Differentiated Thyroid Carcinoma

“…In a bi-institutional study, if compared to planar PT-WBI, PT-SPECT/CT WBI altered patients' risk category in 35.6% of cases, which consequently changed the patient management and follow-up [61].…”