Secretive and proliferative tumor profile helps to select the best imaging technique to identify postoperative persistent or relapsing medullary thyroid cancer

Abstract

In patients with postoperative persistent medullary thyroid cancer (MTC), the tumor detection rate is generally low for most of the imaging techniques now available. The aim of this study was to investigate if the clinico-biological profile of the tumor may indicate which imaging technique to perform in order to identify postoperative persistent or relapsing MTC foci. Thirty-five consecutive MTC patients with detectable and progressively increasing postoperative serum concentrations of calcitonin were enrolled in the study. The detection rates of 18F-deoxy-D-glucose (FDG)-positron emission tomography (PET), somatostatin receptor scintigraphy (SRS), and 131I-metaiodobenzylguanidine scintigraphy (MIBG) were compared in relation with calcitonin and carcinoembryonic antigen serum concentrations, Ki-67 score and results of conventional imaging techniques (CIT). FDG-PET positivity was significantly associated with calcitonin serum concentrations O400 pg/ml and Ki-67 score O2.0% (P!0.05), while SRS positivity was associated with calcitonin serum concentrations O800 pg/ml (P!0.05). SRS positivity significantly correlated with tumor appearance at CIT (P!0.01), while FDG-PET was positive in nine CIT-negative patients. The secretive and proliferative tumor profile may guide the choice of the imaging technique to use in the follow-up of patients with MTC. A Ki-67 score O2.0% suggests to perform a FDG-PET in addition to conventional imaging. Calcitonin secretion predicts both FDG-PET and SRS uptake but SRS positivity is generally found only in patients with well defined MTC lesions that are also detectable at the conventional imaging examination. MIBG outcome is not predicted by any clinico-biological factors here investigated.

Combined RET and Ki-67 assessment in sporadic medullary thyroid carcinoma: a useful tool for patient risk stratification

“…O25 and O50 cells/mm 2 , can predict the presence of distant metastases and the risk of cancerrelated death with a sensitivity of 100% in both cases, and a specificity of 81 and 93% respectively. These data are fully consistent with those reported by Faggiano et al (22) who demonstrated that the MTC proliferative profile is a useful tool for selecting appropriate imaging techniques for persistent MTC patients: in particular, high Ki-67 scores earmarked patients expected to have positive FDG-PET results. In other words, high Ki-67 cutoffs could identify a subset of sporadic MTC cases with an aggressive behavior.…”

Comparison of 18F-DOPA, 18F-FDG and 68Ga-somatostatin analogue PET/CT in patients with recurrent medullary thyroid carcinoma

“…Neuroendocrine tumours usually show an indolent course, and consequently low 18 F-FDG uptake. These tumours, however, when undergoing dedifferentiation become more aggressive and may show increased 18 F-FDG uptake, and this is also the case in MTC as demonstrated by the immunoreactivity for Ki-67 expression in surgically removed lesions [21,22]. When analysing 18 F-FDG PET results on the basis of CTDT, this tracer performs better in patients with higher calcitonin levels (>1,000 pg/ml) and/or with CTDT ≤12 months, again confirming that 18 F-FDG avidity is strictly related to the aggressiveness of the tumour [12,23].…”

Diagnosis and Differential Diagnosis of Medullary Thyroid Cancer

“…Postoperative unsuppressed calcitonin and CEA concentrations may persist elevated during 2-3 months after surgery due to their long half-life in the blood, while increasing calcitonin and CEA serum levels after this time indicate disease persistence and progression (Leboulleux et al, 2004;Pacini et al, 2010;Faggiano et al, 2009). Undetectable basal serum calcitonin levels, further confirmed after a pentagastrin stimulation test, are a strong predictor of complete remission (Pacini et al, 2010).…”

“…The evaluation of the clinico-biological and immunohistochemical tumor profile may be used in order to select the best imagine technique to be performed in patients with postoperative persistent or relapsing MTC. In particular, FDG-PET seems to correlate to tumor proliferation index Ki-67% and to be able to detect metastases in patients with postoperative persistent MTC when conventional imaging techniques are negative (Faggiano et al, 2009) (Figure 4). For advanced MTC, conventional oncological therapies (radiotherapy and systemic chemotherapy) have scarce effectiveness.…”