Cost-effectiveness of 99mTc-MIBI in the evaluation of thyroid nodules for malignancy: a new lease of life for an old radiopharmaceutical?

Abstract

In nuclear medicine practice, physicians are often confronted with the problem that formal registration of a specific radiopharmaceutical and the indications for its use are lacking (e.g. the modern 68 Ga-labelled somatostatin analogues). If formal registration is available, this registration often only covers a few, specific and predominantly commercially interesting indications even when the radiopharmaceutical can be applied more broadly. A good example of the latter is the case of 99m Tc-methoxyisobutylisonitrile (MIBI). MIBI was first described in the 1980s [1,2]. Originally developed for myocardial perfusion scintigraphy for the detection and localization of coronary artery disease, it went on to eventually achieve registration not only for this indication, but also for the assessment of global ventricular function, scintimammography for the detection of suspected breast cancer when mammography is equivocal, inadequate or indeterminate, and localization of hyperfunctioning parathyroid tissue in patients with recurrent or persistent hyperparathyroidism, both primary and secondary, and in patients with primary hyperparathyroidism scheduled to undergo initial surgery of the parathyroid glands [3].However, for many years it has been known that MIBI scintigraphy can also be used in the diagnostic work-up of scintigraphically cold and therefore suspicious thyroid nodules in combination with fine needle biopsy (FNB) [4][5][6][7][8][9][10][11][12] Tc-pertechnetate thyroid scintigraphy MIBI scintigraphy can achieve a very high negative predictive value ranging from 88 % to 100 % with a mean of 97 %. Furthermore, the sensitivity of MIBI scintigraphy is similarly good with an aggregate value of 96 %. This indicates that a negative MIBI scan will obviate the need to surgically remove the thyroid nodule for definitive histological clarification in the large majority of patients, as the risk of malignancy in such a nodule is very low.This of course does have economic implications. Considering that the risk of missing the diagnosis of thyroid cancer is low, and a large number of, in hindsight unnecessary, comparatively expensive surgical procedures can be avoided, it is not surprising that Wale et al. are able to show that the addition of MIBI scintigraphy leads to a considerable saving in costs per patient and per cancer diagnosed while not significantly affecting life expectancy [13].Of course, the model used by Wale et al. is a theoretical one and any model requires simplification of the sometimes complex individual situations of different patients. For example, the authors did not directly assess the life expectancy of patients scanned with MIBI, but derived these data from unrelated survival analyses of patients with thyroid cancer. This and further notable limitations of the model are mainly due to the lack of data from prospective randomized controlled trials.

Endocrine Scintigraphy with Hybrid SPECT/CT

“…Economic evaluation studies in nuclear medicine in the pre-SPECT/CT era have predominately been focused on proving the effectiveness of PET for cancer staging and myocardial perfusion studies for the diagnosis of coronary artery disease (CAD). For endocrine disorders, cost-effectiveness has been reported for radioiodine as first line treatment of Graves hyperthyroidism compared to surgery (294), radioiodine uptake (RAIU) measurements in the diagnostic work-up of thyrotoxicosis (295), evaluation of thyroid nodule malignant potential with sestamibi scans (296,297), staging of NETs using somatostatin scintigraphy (298) (299), work-up of adrenal incidentaloma with NP-59 imaging (300) (301) and use of 131 I-MIBG therapy for treatment of carcinoid syndrome (302). Parathyroid scintigraphy for preoperative localization of adenomas is cost-effective as the costs of protracted or failed surgery due to an unidentified ectopic adenoma outweigh those related to 53-year-old woman with hypothyroidism had progressive globus sensation and symptoms of airway obstruction when lying supine.…”

Update 2019 zur MIBI-Szintigrafie bei hypofunktionellen Schilddrüsenknoten

“…Wale et al analysierten 108 Patienten mit hypofunktionellen Schilddrüsenknoten und betonen den hohen negativen prädiktiven Wert der 99 m Tc-MIBI-Szintigrafie [54]. Der Ausschluss von Malignität erlaubte ein kosteneffizientes Patientenmanagement.…”

“…Heinzel et al analysierten 99 m Tc-MIBI im Vergleich zu einer Genexpressionsanalyse (Afirma ® gene expression classifier) bei Schilddrüsenknoten mit nicht diagnostischer FNAB. Die Strategie unter Verwendung von 99 m Tc-MIBI war hier kostengünstiger (1459 € für 99 m Tc-MIBI versus 3560 € für die Genexpressionsanalyse) [15,54].…”

Comparison of F-18 FDG-PET/CT and Tc-99m MIBI in the preoperative evaluation of cold thyroid nodules in the same patient group

“…MIBI scintigraphy in combination with FNAB has been used for many years, in the diagnosis of scintigraphically cold and therefore suspicious thyroid nodules [9]. Nowadays, FDG-PET/CT is commonly used in clinical practice, which has led to an increase in the detection of incidentalomas.…”