1050P - Whole-body diffusion MRI and skeletal lesions in thyroid cancer: diagnostic and therapeutic implications

Date 01 October 2012
Event ESMO Congress 2012
Session Poster presentation III
Topics Thyroid Cancer
Imaging, Diagnosis and Staging
Presenter Laura Locati
Authors L. Locati1, R. Granata2, P. Potepan3, G. Aliberti4, E. Civelli5, P. Bossi2, E. Montin3, L. Licitra2
  • 1Head & Neck Unit, Fondazione IRCCS - Istituto Nazionale dei Tumori, 20133 - Milano/IT
  • 2Oncologia Medica, Fondazione IRCCS - Istituto Nazionale dei Tumori, 20133 - Milano/IT
  • 3Department If Radiodiagnostic, Fondazione IRCCS - Istituto Nazionale dei Tumori, 20133 - milano/IT
  • 4Department Of Nuclear Medicine, Fondazione IRCCS - Istituto Nazionale dei Tumori, 20133 - milano/IT
  • 5Department Of Diagnostic Imaging And Radiotherapy, Fondazione IRCCS - Istituto Nazionale dei Tumori, 20133 - milano/IT

Abstract

Background

Forty-fifty percent of the patients with metastatic TC suffer from bone metastases. 99mTc scintigraphy is employed to assess bone lesions although it lacks of accuracy, mostly in lytic lesions of differentiated thyroid cancer (DTC). CT scan has a sensitivity of 71-100% while data on the accuracy of 18F-FDG-PET/CT are scanty. MRI captures both bone and bone marrow involvement, more common in medullary thyroid cancer (MTC). Whole body MRI (WB) and whole-body diffusion (WB-DWI) are emerging as accurate tools for detection and therapy monitoring of bone metastases. We investigated the role of WB and WB-DWI in bone lesions from TC i) sensitivity and specificity; ii) evaluation of response during TKIs.

Material and methods

Radiological records of patients with metastatic TC submitted to WB-DWI at the baseline staging were reviewed. For our first purpose, patients with at least one another bone imaging were included. A false-positive was a positive bone imaging not confirmed by histopathology or/and another imaging technique or by two imaging exams. A false-negative was a negative finding on bone imaging and a positive one on another imaging method plus histopathology or by two imaging methods. For each imaging modality, sensitivity, specificity and accuracy were calculated. For the secondary aim were considered only patients scanned by WB-DWI at baseline and during TKIs treatment.

Results

Since 2010, nine MTC (5M/4F) and five DTC (3M/2F) patients were selected. Results of the first aim are listed in the table.

WB-DWI Bone scan Bone CT
Number of exams 14 12 12
True-positive 10 8 8
True-negative 4 4 4
False-positive 0 1 (MTC) 0
False-negative 0 1 (DTC) 1 (MTC)
Sensitivity % 100 88 88
Specificity % 100 80 100
Accuracy % 100 86 92

In five (4 MTC/1 DTC) out eight (62%) true-positive bone scan, WB-DWI demonstrated a higher number of bone lesions. In three patients (2 MTC/1 DTC), WB-DWI showed a cystic evolution in the responding lesions during TKI (apart from the histotype).

Conclusions

In our hands WB-DWI is the best imaging method to identify bone lesions from TC. It could potentially address unmet clinical and therapeutic needs for a reliable measure of bone lesion response in this rare tumors.

Disclosure

All authors have declared no conflicts of interest.