Detection of Thyroid Tumours Using Radio‐labelled Anti‐thyroglobulin

Abstract

IgG antibody to human thyroglobulin was labelled with 131Iodine (131I) and used to locate deposits of thyroid follicular and papillary tumours with a gamma camera. Of twelve patients studied a total of 40 tumour 'areas' were detected by a variety of clinical and radiological techniques. Sixteen of these were detected using conventional 131I uptake scans whereas 34 were positive on the antibody scans. The difficulty of assessing diffuse pulmonary lesions (3 areas) and the possibility that free 131I from labelled antibody may have contributed to the antibody scan results in six areas left 31 definite areas for scan comparison. Twenty seven (87%) areas were positive on the antibody scan, nine (29%) were positive on conventional 131I scans whilst 24 (77%) areas were detected by a combination of clinical and other radiological criteria. Five areas were positive on the antibody scan alone but there was evidence, albeit indefinite, that these areas contained tumour. Four of the 31 areas were not detected by the antibody scans. The results indicate that anti-thyroglobulin scanning is more sensitive than conventional 131I-iodide scans and may contribute to the staging and management of thyroid cancer.

How to deal with undetectable and low measurable serum thyroglobulin levels in the follow-up of patients with differentiated thyroid carcinoma?

“…With our policy false-negative Tg levels seem to be avoided at least when iodine accumu¬ lating cancer tissue is detectable. The localization of scintigraphically negative métastases should then be pur¬ sued by clinical investigation, chest X-rays, bone scanning, computerized tomography and labelled antibodies (Fairweather et al 1983). Nevertheless, the number of control studies could be reduced and the diagnostic potential of the Tg determination increased if all patients with differentiated thyroid carcinoma were subjected to complete thyroidec¬ tomy and, if required, to radioablation of the residual tissue as pointed out by Schneider et al (1981).…”

Radioimmunodetection of malignant solid tumours

“…Positive localization of follicular and papillary thyroid cancer deposits was achieved in 12 patients with I-131-labelled polyclonal antibody to human thyroglobulin [87]. Of a total of 40 lesions 34 were detected by RAID, whereas only 16 were positive on I-131-iodide (37MBq) scans, indicating that anti-thyroglobulin scintigraphy is more sensitive than the conventional imaging method.…”

Thyroid Function Testing

“…178 Scanning with 131 I-labeled anti-TG for the detection of occult metastatic thyroid malignancy that fails to concentrate 131 I showed early promising results. 179 However, the procedure has not proved clinically useful.…”