18F]DOPA PET/ceCT in diagnosis and staging of primary medullary thyroid carcinoma prior to surgery

Sazan Rasul,Marius Mayerhoefer,Georgios Karanikas,Marcus Hacker,Adelina Göllner,Sabrina Hartenbach,Peter Mazal,Katharina Rebhan,Markus Hartenbach

doi:10.1007/s00259-018-4045-9

Sazan Rasul, Marius Mayerhoefer + Show 7 more

Open Access

https://doi.org/10.1007/s00259-018-4045-9

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Abstract

PurposeMedullary thyroid carcinoma (MTC) is characterized by a high rate of metastasis. In this study we evaluated the ability of [18F]DOPA PET/ceCT to stage MTC in patients with suspicious thyroid nodules and pathologically elevated serum calcitonin (Ctn) levels prior to total thyroidectomy and lymph node (LN) dissection.MethodsA group of 32 patients with sonographically suspicious thyroid nodules and pathologically elevated basal Ctn (bCtn) and stimulated Ctn (sCtn) levels underwent DOPA PET/ceCT prior to surgery. Postoperative histology served as the standard of reference for ultrasonography and DOPA PET/ceCT region-based LN staging. Univariate and multivariate regression analyses as well as receiver operating characteristic analysis were used to evaluate the correlations between preoperative and histological parameters and postoperative tumour persistence or relapse.ResultsPrimary MTC was histologically verified in all patients. Of the 32 patients, 28 showed increased DOPA decarboxylase activity in the primary tumour (sensitivity 88%, mean SUVmax 10.5). Undetected tumours were exclusively staged pT1a. The sensitivities of DOPA PET in the detection of central and lateral metastatic neck LN were 53% and 73%, in contrast to 20% and 39%, respectively, for neck ultrasonography. Preoperative bCtn and carcinoembryonic antigen levels as well as cN1b status and the number of involved neck regions on DOPA PET/ceCT were predictive of postoperative tumour persistence/relapse in the univariate regression analysis (P < 0.05). Only DOPA PET/ceCT cN1b status remained significant in the multivariate analysis (P = 0.016, relative risk 4.02).ConclusionThis study revealed that DOPA PET/ceCT has high sensitivity in the detection of primary MTC and superior sensitivity in the detection of LN metastases compared to ultrasonography. DOPA PET/ceCT identification of N1b status predicts postoperative tumour persistence. Thus, implementation of a DOPA-guided LN dissection might improve surgical success.

Highlights

Medullary thyroid cancer (MTC) is a rare type of neuroendocrine tumour, that accounts for less than 5% of all thyroid cancer cases
Levels of basal Ctn (bCtn), stimulated Ctn (sCtn) and carcinoembryonic antigen (CEA) were measured in every patient preoperatively as well as postoperatively and during followup using commercially available assays
Total thyroidectomy with central and bilateral neck dissection was performed in 23 patients (72%) as standard at our institution in this cohort of patients with high Ctn levels

Summary

Introduction

Medullary thyroid cancer (MTC) is a rare type of neuroendocrine tumour, that accounts for less than 5% of all thyroid cancer cases. It originates from C cells and is situated within the outer follicle walls of the thyroid gland. It occurs as either a familial or a sporadic form. The sporadic form accounts for about 75% of all MTC and it mostly occurs in adults aged between 40 and 60 years [1].

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