Trial Information

Optical Probe In Thyroid Cancer

Background: Thyroid cancer is the most common endocrine malignancy. The current gold
standard, fine-needle aspiration (FNA) biopsy, yields approximately 10-25% of indeterminate
results, leading to patients undergoing thyroidectomy for diagnosis. Elastic scattering
spectroscopy (ESS) is a new, minimally invasive optical-biopsy technique, mediated by
fiber-optic probes, that which is sensitive to cellular and sub-cellular morphological
features. We assessed the potential to incorporate an ESS probe into a 23-gauge needle
biopsy to use in preoperative trans-cutaneous biopsy of the thyroid to differentiate benign
from malignant thyroid nodules.

Methods: We designed and built a miniaturized ESS probe that can fit through a 23-gauge
biopsy needle and tested it under an IRB-approved protocol on 34 patients undergoing
ultrasound-guided FNA biopsy of thyroid nodules in the endocrine clinic. ESS data was
collected during the conduct of their biopsy using optical 5 repetitive readings from three
distinct locations within the thyroid nodule. Using cytology as our gold standard, spectral
analyses were compared between benign and malignant thyroid nodules. For indeterminate
cytology, final post-surgery pathology of the tissue was used for the comparison.

Results: All patients tolerated the procedure well and the additional time required for the
ESS measurements was usually less than 30 seconds.under one minute. Initial analysis
demonstrates that cellularity from the biopsy specimen was adequate for diagnosis, and
spectra could be collected on all patients. Spectral appearance clearly differed between
solid and liquid components portions of the thyroid nodule. Spectral analysis demonstrates a
sensitivity to hemoglobin density. and ambient light, and a A signature of difference in
waveforms could discriminate benign from malignant disease.

Conclusion: It is feasible to collect cytological material and ESS data real-time during an
ultrasound-guided FNAB using a miniaturized combined ESS-biopsy needle probe in the usual
clinical setting. The cytological specimen is adequate compared to conventional FNA biopsy,
and the ESS data from this miniaturized optical probe is is of comparable quality to the
standard ESS probe used in the diagnosis of other malignancies. Preliminary analysis reveals
that there is a unique waveform signature that can differentiate benign from malignant
thyroid nodules, using cytology or (or post-surgically histopathology) as the gold standard.
With the collection of further data, an algorithm using ESS collected using our novel
miniaturized ESS biopsy probe could potentially be used as an in-situ real time
intra-operative diagnostic tool or as a minimally invasive adjunct to conventional FNA
cytology with ultrasound or CT guidance.