RT-PCR supported thyroglobulin detection in fine needle biopsy from neck lymph node metastases of differentiated thyroid carcinoma

E Gubala, PhD, D Handkiewicz-Junak, MD, M Zeman, MD, E Chmielik, MD, M Wiench, PhD, K Woloszynska MD, B Jarzab MD, PhD

Dept. of Nuclear Medicine and Endocrine Oncology, Center of Oncology – Maria Sklodowska-Curie Memorial Institute, Gliwice Branch, Poland, e-mail

Differentiated thyroid cancer (DTC) cells preserve their ability to express thyroglobulin (Tg). In the follow up of the patients RT-PCR Tg may support the interpretation of fine needle biopsy results where classical cytological examination fails to detect lymph node metastases early enough Aim: Prospective evaluation of thyroglobulin mRNA detection in neck lymph nodes in DTC patients. Material & Methods: Thyroglobulin RT-PCR was conducted in the residual material left after preparation of cytological smears from fine needle biopsy aspirates of 102 patients suspected for local DTC recurrence with the mean follow-up time of 8 months. 35 patients with other types of cancer were included. We also included 20 lymph nodes examined by needle biopsy during operation of 8 patients with DTC as a control group. Results: Cytology confirmed nodal involvement in 49 of DTC patients, RT-PCR Tg was positive in 47 of them and the two RT-PCR negative results were confirmed as false negatives by pathological examination following surgery (sensitivity: 96%). Among cytology negative specimens, 8 RT-PCR positive results were obtained. In three patients in whom Tg mRNA was not confirmed by cytology examination the DTC neck recurrence was confirmed a few months later by the next biopsy and a subsequent postoperative pathological examination. Positive RT-PCR results preceded the clinical detection of metastases by more 7 months. The specificity of the method is evaluated with 95%. Conclusions: Thyroglobulin RT-PCR may be regarded as a valuable tool supporting the early detection of local recurrence of differentiated thyroid carcinoma.

KEY WORDS: thyroglobulin, differentiated thyroid cancer, fine needle biopsy.

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Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Paris, France; February 9 - 12, 2002; in the section on Diagnostic Markers.