Endocrine Abstracts

Historically, the ¹³¹I whole body scan played a central role in the assessment of disease status in patients with differentiated thyroid cancer.

In 2006, the European Thyroid Cancer Taskforce published a new Consensus Statement. It favoured the use of stimulated serum thyroglobulin measurement and neck ultrasound for follow up of disease activity. The use of diagnostic ¹³¹I whole body scan was no longer recommended as a routine test.

Our objective was to assess if the use of ¹³¹I whole body scan provided additional clinical information beyond the combined use of neck ultrasound and stimulated thyroglobulin measurement in follow up of patients with differentiated thyroid cancer.

We retrospectively analysed the data from 41 patients who entered our surveillance programme between February 2007 and July 2009.

¹³¹I whole body scan and serum thyroglobulin measurements were performed after recombinant TSH administration (n=35) or thyroxine withdrawal (n=6). All patients underwent simultaneous diagnostic neck ultrasound.

Disease activity was suggested by stimulated thyroglobulin levels >1 μg/l in four patients. Ultrasound of the neck was abnormal in two of the four. Further investigations with computed tomography revealed pulmonary metastases in two of the four.

¹³¹I whole body scan showed abnormal uptake in three of these patients, failing to discriminate pulmonary metastases in one patient.

Conversely, ¹³¹I whole body scan showed residual uptake in six patients with no other evidence of disease activity.

The concordance between ¹³¹I whole body scan and combined use of neck ultrasound and stimulated thyroglobulin measurements was demonstrated in only 83% of patients.

In our clinical practice, the routine use of ¹³¹I whole body scan is an inaccurate determinant of disease status in follow up of patients with differentiated thyroid cancer.

This retrospective study confirms that the exclusion of this investigation from our surveillance programme would not have resulted in loss of clinical information.