Detecting Recurrence Following Lobectomy for Differentiated Thyroid Cancer: The Role of Thyroglobulin and Anti-thyroglobulin Antibodies

  • Background: Response to therapy assessment tool is well validated for patients with thyroid cancer following total-thyroidectomy and radioiodine, but limited data is available for patients treated with lobectomy.

    Methods: Patients who had lobectomy for DTC, followed for >1 year without completion thyroidectomy, and had sufficient data on Tg and TgAb.

    Results:  A total of 167 patients met inclusion criteria. Lobectomy was performed for classic papillary thyroid cancer (PTC) in 69%, follicular variant PTC in 29%, and other variants in 2%. Average tumor size was 9.5±6mm. Following lobectomy, Tg was 12.1±14.8ng/ml. Of 52 patients with HT, 38% had positive TgAb with titers of 438±528IU/mL, and 69% had no TgAb, with Tg levels of 13.5±18.4ng/ml. In 30 patients with contralateral nodules ?1cm, Tg was 15.3±17ng/ml. During the first two years of follow-up, Tg declined ?1 ng/ml in 40% of patients (by 6.5±6.2ng/ml), remained stable in 25%, and increased in 35% (by 5±5.7ng/ml). During 78±43.5 months of follow-up, 18 patients had completion thyroidectomy and twelve diagnosed with contralateral cancer (n=8) or lymph node metastases (n=4). In patients with recurrence followed for >2 years, there was a steady rise in Tg in three cases, Tg was stable in two cases, and in one TgAb decreased from 1534 to 276 despite metastatic lymph-node. Basal Tg and Tg dynamics did not predict disease recurrence.   

    Conclusions: Thyroglobulin used independently is of limited value to predict or detect locoregional recurrence following lobectomy. Other potential roles of Tg, such as excluding distant metastases following lobectomy should be further studied.

 

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