Intraoperative MET-receptor targeted fluorescent imaging and spectroscopy for lymph node detection in papillary thyroid cancer: novel diagnostic tools for more selective central lymph node compartment dissection

Eur J Nucl Med Mol Imaging. 2022 Aug;49(10):3557-3570. doi: 10.1007/s00259-022-05763-3. Epub 2022 Apr 7.


Purpose: Patients undergoing prophylactic central compartment dissection (PCLND) for papillary thyroid cancer (PTC) are often overtreated. This study aimed to determine if molecular fluorescence-guided imaging (MFGI) and spectroscopy can be useful for detecting PTC nodal metastases (NM) and to identify negative central compartments intraoperatively.

Methods: We used a data-driven prioritization strategy based on transcriptomic profiles of 97 primary PTCs and 80 normal thyroid tissues (NTT) to identify tumor-specific antigens for a clinically available near-infrared fluorescent tracer. Protein expression of the top prioritized antigen was immunohistochemically validated with a tissue microarray containing primary PTC (n = 741) and NTT (n = 108). Staining intensity was correlated with 10-year locoregional recurrence-free survival (LRFS). A phase 1 study (NCT03470259) with EMI-137, targeting MET, was conducted to evaluate safety, optimal dosage for detecting PTC NM with MFGI, feasibility of NM detection with quantitative fiber-optic spectroscopy, and selective binding of EMI-137 for MET.

Results: MET was selected as the most promising antigen. A worse LRFS was observed in patients with positive versus negative MET staining (81.9% versus 93.2%; p = 0.02). In 19 patients, no adverse events related to EMI-137 occurred. 0.13 mg/kg EMI-137 was selected as optimal dosage for differentiating NM from normal lymph nodes using MFGI (p < 0.0001) and spectroscopy (p < 0.0001). MFGI identified 5/19 levels (26.3%) without NM. EMI-137 binds selectively to MET.

Conclusion: MET is overexpressed in PTC and associated with increased locoregional recurrence rates. Perioperative administration of EMI-137 is safe and facilitates NM detection using MFGI and spectroscopy, potentially reducing the number of negative PCLNDs with more than 25%.

Clinical trial registration: NCT03470259.

Keywords: Lymph node imaging; Molecular fluorescence-guided imaging; Papillary thyroid cancer; Spectroscopy.

MeSH terms

  • Carcinoma* / pathology
  • Carcinoma, Papillary* / diagnostic imaging
  • Humans
  • Lymph Nodes / pathology
  • Neoplasm Recurrence, Local / pathology
  • Spectrum Analysis
  • Thyroid Cancer, Papillary / diagnostic imaging
  • Thyroid Neoplasms* / pathology
  • Thyroidectomy

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