Critical evaluation of serum thyroglobulin (Tg) levels during thyroid hormone suppression therapy versus Tg levels after hormone withdrawal and total body scan: results in 291 patients with thyroid cancer.
Serum thyroglobulin (Tg) levels were measured during thyroid-hormone suppressive therapy in 291 patients who had been treated for well-differentiated thyroid carcinoma. The findings were compared with those of a subsequent total body scan (TBS) and with Tg levels measured after thyroid-hormone withdrawal. Of the patients with low Tg levels during suppressive therapy, 91.6% were subsequently shown to be free of disease or to have only remnants in the thyroid bed, whereas 8.4% had metastases (false-negative). Of the patients with false-negative findings, 89.3% had nodal metastases; 60.8% of the patients with nodal metastases exhibiting radioiodine uptake and only 23% of those with nonfunctioning nodal metastases had low Tg levels during suppression therapy. After thyroid-hormone withdrawal, all but 1 of the patients with nodal metastases had high Tg levels. All but 2 of the patients with distant metastases had high Tg levels during suppression therapy; 1 of these 2 patients exhibited high Tg levels after T3 withdrawal. No differences between Tg levels in patients with functioning and non-functioning metastases were found. Our study indicates that Tg assays performed during suppressive therapy have a fairly good predictive value and can be used as a general guide in the follow-up of thyroid cancer. However, since most differentiated metastases produce Tg only when stimulated by thyroid-stimulating hormone, measurements of Tg levels after the discontinuation of suppressive therapy would also seem to be necessary.
Girelli
M E
ME
Busnardo
B
B
Amerio
R
R
Casara
D
D
Betterle
C
C
Piccolo
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000000981:diagnostic imaging; D011863:Radioimmunoassay; D011877:Radionuclide Imaging; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood* / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000601:surgery; D013965:Thyroidectomy; D013972:Thyrotropin / Q000008:administration & dosage / Q000097:blood; D013973:Thyrotropin-Releasing Hormone; D014284:Triiodothyronine / Q000627:therapeutic use*
D014284:Triiodothyronine; D013973:Thyrotropin-Releasing Hormone; D013972:Thyrotropin; D013954:Thyroglobulin