Recombinant thyrotropin for detection of recurrent thyroid cancer.
Detection of recurrent thyroid cancer tumor requires TSH stimulation for radioiodine scanning and thyroglobulin (Tg) measurement. Temporary thyroid hormone withdrawal has previously been used, but causes hypothyroidism and, rarely, tumor progression.


METHODS
The alternative of recombinant thyrotropin (rTSH) was assessed in two randomized clinical trials in which patients had 131I and Tg testing twice: first after rTSH, and second after thyroid hormone withdrawal. Test results and quality of life were compared.


RESULTS
In the first trial, among 62 of 127 patients with positive scans, rTSH was equivalent to withdrawal in 41, superior in 3, and inferior in 18 (P < 0.05), suggesting a lesser sensitivity of rTSH scans. In a second trial employing enhanced techniques, among 108 of 220 patients with positive scans, there was no difference in the number of superior rTSH and withdrawal scans. Furthermore, among all patients with withdrawal study evidence of residual thyroid tissue, 74% of all patients with residual thyroid tissue and 100% of patients with tumor metastases had rTSH-stimulated thyroglobulin values above 2 ng/mL. Naturally, patients experienced significantly more symptoms and diminished quality of life when hypothyroid than after rhTSH.


CONCLUSIONS
Combined rTSH-stimulated radioiodine and Tg testing is as sensitive as thyroid hormone withdrawal to detect recurrent thyroid cancer, and causes less morbidity.
Ladenson
Paul W
PW
Division of Endocrinology and Metabolism, Johns Hopkins University School of Medicine, 1830 E. Monument Street, Suite 333, Baltimore, Maryland 21287, USA. ladenson@jhmi.edu
D002985:Clinical Protocols; D006801:Humans; D007457:Iodine Radioisotopes; D009364:Neoplasm Recurrence, Local / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D011877:Radionuclide Imaging; D011994:Recombinant Proteins; D012680:Sensitivity and Specificity; D013954:Thyroglobulin / Q000097:blood; D013963:Thyroid Hormones / Q000627:therapeutic use; D013964:Thyroid Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000188:drug therapy; D013972:Thyrotropin
D007457:Iodine Radioisotopes; D011994:Recombinant Proteins; D013963:Thyroid Hormones; D013972:Thyrotropin; D013954:Thyroglobulin