Outcome in patients with differentiated thyroid cancer with negative diagnostic whole-body scanning and detectable stimulated thyroglobulin

Abstract

Background: Management of patients with differentiated thyroid carcinoma with negative diagnostic radioiodide scanning and increased serum thyroglobulin (Tg) concentrations is a widely debated problem. High-dose iodine-131 treatment of patients who have a negative 131 I diagnostic wholebody scan (WBS) is advocated. However, the therapeutic benefit of this 'blind' treatment is not clear. Objective: To investigate the course of serum Tg during thyroid hormone suppression therapy (Tg-on) and clinical outcome in patients with negative diagnostic 131 I scanning and increased serum Tg concentrations during thyroid hormone withdrawal (Tg-off), after treatment with high-dose 131 I. Design: Retrospective single-center study. Methods: Fifty-six patients were treated with a blind therapeutic dose of 150 mCi 131 I. Median followup from this treatment until the end of observation was 4.2 years (range 0.5 -13.5 years). Results: The post-treatment WBS revealed 131 I uptake in 28 patients, but none in the remaining 28 patients. In this study the Tg-on values did not change after treatment in either the positive or the negative post-treatment WBS group. During follow-up, 18 of the 28 patients with a positive posttreatment WBS achieved complete remission, compared with 10 of the 28 patients with a negative post-treatment WBS. Nine patients in the negative group died, but no patients died in the positive post-treatment group (P ¼ 0.001). Conclusions: High-dose iodine treatment in diagnostically negative patients who have a negative posttreatment scan seems to confer no additional value for tumor reduction and survival. In patients with a positive post-treatment scan, high-dose iodine treatment can be used as a diagnostic tool to identify tumor location, and a therapeutic effect may be present in individual cases.

Management Guidelines for Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Taskforce

“…4). This approach may identify the location of persistent disease in approximately 50% of patients (203,280) with a wide range of reported success. Some investigators have reported a decrease in serum thyroglobulin after empiric radioiodine therapy in patients with negative RxWBS (281,282), but there is no evidence for improved survival with empiric therapy in this setting (258,283).…”

“…A cutoff value of thyroglobulin above which a patient should be treated with an empiric dose of radioiodine is difficult to determine, in part because of the wide variation in available thyroglobulin assays (including those used in reports suggesting benefit of such therapy) and the differences in thyroglobulin levels based on method and degree of TSH stimulation or suppression. Recent studies have reported primarily on patients with thyroglobulin levels after thyroxine withdrawal of 10 ng/mL or higher, and it has been suggested that a corresponding level after rTSH stimulation would be 5 ng/mL (204,256,280,282,283). A thyroglobulin level that is rising may warrant greater concern for the need for empiric therapy, although data regarding the appropriate rate of change are minimal (202).…”

Our initial experiences related to gamma probe use in completion thyroidectomy

“…Gamma prob ile tamamlayıcı tiroidektomiden 6 hafta sonra radyoaktif I-131 tedavisi verilebilir (9). Serum tiroglobulin (Tg) ölçümü ve radyoaktif I-131 taraması birbirini tamamlayıcı yöntemlerdir (10 …”

Molecular technology and the recombinant TSH have changed diagnostics of thyroid carcinoma with positive I-131 whole body scan but low serum thyroglobulin

“…Patients with elevated Tg levels, but negative 131 I WBS, are usually not treated with high-dose 131 I. In fact, the therapeutic benefit of a "blind" radioiodine treatment is not clear (van Tol et al, 2003). The detection of neoplastic foci not seen with diagnostic doses of 131 I by other imaging techniques may identify patients candidate to treatment.…”