Unexpected False-positive I-131 Uptake in Patients with Differentiated Thyroid Carcinoma

Oral, Aylin; Yazıcı, Bülent; Eraslan, Cenk; Burak, Zeynep

doi:10.4274/mirt.37450

Cited by 16 publications

(14 citation statements)

References 21 publications

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“…Overall, the literature showed 145 case reports and two series regarding false-positive 131 uptake after RIT For the reasons stated above, we excluded 129 papers, considering only those in which SPECT/CT was performed. A total of 18 papers were thus included: 1 series [17] and 17 case reports [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]. The series reported 23 cases of falsepositive results: 15 in the chest, six in the pelvis, one in the cranium, and one in the abdomen.…”

Section: Resultsmentioning

confidence: 99%

False-positive radioiodine uptake after radioiodine treatment in differentiated thyroid cancer

Bari¹,

Campennì

Forleo³

et al. 2023

Endocrine

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Background and purpose False-positive radioiodine uptake can sometimes be observed with post-radioiodine treatment (RIT) whole body scanning. Radioiodine pitfall has often been reported as being caused by benign or inflammatory disease, or, in some cases, by tumor lesions. This paper reviews the possible causes of such false-positive imaging, and suggests possible reasons for suspecting these pitfalls. Methods and results Online databases, including MEDLINE (via PubMed), Embase, ISI Web of Science, Google Scholar, and Scopus, were systematically examined, using different keyword combinations: "radioiodine false-positive imaging", "131 I false-positive imaging" and " RAI false-positive imaging". An illustrative case was described. Excluding cases in which SPECT/CT was not performed, a total of 18 papers was found: 17 case reports and one series regarding false-positive iodine-131 uptake after RIT. Conclusions The prevalence of radioiodine pitfall was significantly reduced through the use of SPECT/CT imaging, though its possible presence has always to be taken into account. Inflammation, passive iodine accumulation, other tumors, and, sometimes, unknown causes can all potentially generate false-positive imaging. Missing detection of false-positive imaging could result in over-staging and inappropriate RIT or it could lead to the non-detection of other cancers. We examine the reasons for these possible pitfalls.

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Section: Resultsmentioning

confidence: 99%

False-positive radioiodine uptake after radioiodine treatment in differentiated thyroid cancer

Bari¹,

Campennì

Forleo³

et al. 2023

Endocrine

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“…Garger et al showed that the incidence of ptWBS false-positives is around 73 % with predominance for focal uptake. The etiology of false-positive uptakes cannot be determined in one-third of patients [17,30]. Accordingly, we analyzed ptWBS after the first activity of RAI and found five false-positive results patterns.…”

Section: Discussionmentioning

confidence: 97%

Reappraising the Diagnostic Accuracy of Post-Treatment Whole-Body Scans for Differentiated Thyroid Carcinoma

et al. 2020

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Initial treatment for differentiated thyroid carcinoma (DTC) often consists of surgery and the administration of radioiodine. In this context, post-treatment Whole-Body Scans (ptWBS) are currently recommended, but data on its diagnostic accuracy are rare. The aim of the study was to evaluate the performance of ptWBS for distant metastasis in DTC patients. We included DTC patients who received radioiodine and underwent ptWBS between 2009–2015. The medical data were independently reviewed by two specialists to evaluate the concordance of positive distant ptWBS uptake and distant metastasis documented by imaging exams (gold standard). We studied 268 DTC patients. The mean age was 46±16 years (82% women), and papillary thyroid carcinoma was diagnosed in 87% of the patients. The median tumor size was 2.7 cm, 40% had lymph node involvement, and 11% had distant metastasis. Twenty-eight patients (10%) had distant ptWBS uptake, and nine of them (32%) were false-positives. In addition, nine false-negative ptWBS uptakes were identified. The overall performance of ptWBS showed 68% sensitivity and 96% specificity with significantly different performance according to the American Thyroid Association (ATA) risk groups. While the ptWBS performance for ATA low-intermediate-risk showed 29% sensitivity, 97% specificity, and Kappa of 0.19, the ATA high-risk group ptWBS displayed high sensitivity (82%), specificity (100%), and good agreement (Kappa 0.74). ptWBS is useful for a subgroup of ATA high-risk DTC patients. The overall poor performance of ptWBS suggests that it should be reconsidered for routine use in ATA at low to intermediate risk: the exam has little value to this subgroup.

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“…Post-treatment whole body scans (ptWBS) are currently recommended in patients receiving RAI therapy. However, the accuracy of DX-WBS for identification of metastasis is controversial (36,37). Nava et al reported a sensitivity of 29% and a specificity of 97% for DX-WBS in ATA low-intermediaterisk DTC patients, indicating it should be reconsidered for routine DX-WBS in this subgroup (38).…”

Section: Discussionmentioning

confidence: 99%

An immediate postoperative response to therapy assessment can help avoid unnecessary RAI therapy

Zhao

Liu²,

Cao³

et al. 2022

Front. Oncol.

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BackgroundRadioiodine (RAI) therapy plays a vital role in the postoperative treatment of differentiated thyroid cancer (DTC) patients underwent total thyroidectomy (TT). However, even in the presence of capsular invasion and lymph node metastasis prognosis can be excellent and a postoperative RAI treatment might not be necessary for all patients. Therefore, this study explored the criteria for avoiding unnecessary RAI therapy in these patients.MethodWe applied response to therapy assessment immediately after surgery and prospectively recruited 179 excellent or indeterminate response DTC patients with capsular invasion and/or LNM who underwent TT without RAI therapy. During the follow-up, thyroglobulin (Tg), thyroglobulin antibody (TgAb) levels, and cervical ultrasonography were collected and analyzed. Disease-free survival (DFS) was calculated using the Kaplan-Meier method. In addition, response to therapy assessments was performed on patients during each follow-up.ResultsThe mean follow-up period was 29.85 ± 17.44 months, and the 3- and 5-year DFS for all the patients was 99.3% in each. At the last follow-up, 165 (92.2%) patients had excellent responses, while 12 (6.7%) had an indeterminate response, and one (0.6%) each had biochemical and incomplete responses. No significant difference was observed in response to therapy between the subgroups of LNM and tumor invasion (P>0.05). For patients with capsular invasion and a number of metastatic lymph nodes ≤5 and >5, the proportions of recorded excellent responses were 95.9%, 91.0%, and 85.7%, respectively. Better responses were observed in females (excellent response: 95.5%, P=0.023), patients with stimulated Tg (s-Tg) ≤1ng/ml (excellent response: 100%, P<0.001), s-Tg ≤ 2ng/ml (excellent response: 98.4%, P<0.001), and excellent response for the immediate postoperative assessment (excellent response: 98.5%, P=0.004).ConclusionsThe current study suggested that the response to therapy assessment immediately applied postoperatively could help avoid unnecessary RAI therapy among DTC patients with capsular invasion and/or LNM. Moreover, excellent response patients and patients with indeterminate response and s-Tg ≤ 2ng/ml could be managed without RAI therapy.

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Unexpected False-positive I-131 Uptake in Patients with Differentiated Thyroid Carcinoma

Cited by 16 publications

References 21 publications

False-positive radioiodine uptake after radioiodine treatment in differentiated thyroid cancer

False-positive radioiodine uptake after radioiodine treatment in differentiated thyroid cancer

Reappraising the Diagnostic Accuracy of Post-Treatment Whole-Body Scans for Differentiated Thyroid Carcinoma

An immediate postoperative response to therapy assessment can help avoid unnecessary RAI therapy

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