Use of an In Vivo Optical Probe to Discriminate Benign From Malignant Thyroid Nodules

• Assess optical probe for the differentiation of thyroid cancer from normal thyroid tissue and benign thyroid nodules [ Time Frame: 2 years ] [ Designated as safety issue: Yes ]
  The objective is to assess a device called an optical probe for the differentiation of thyroid cancer from normal thyroid tissue, benign thyroid nodules or parathyroid glands, and the detection of thyroid cancer within lymph nodes. The gold standard for diagnosis is ultrasound guided fine needle aspiration biopsy of the nodule. Based on cytology from Fine Needle Aspiration (FNA), 10% of nodules are cancer, 70% are benign (not cancer) and 20% are "indeterminate." The proposed device aims to decrease the number of patients that undergo surgery for diagnosis.
  
  

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.