Detecting recurrence following lobectomy for thyroid cancer: Role of thyroglobulin and thyroglobulin antibodies

Abstract

Background: The use of thyroglobulin (Tg) and thyroglobulin antibodies (TgAb) for detectingdisease recurrence is well validated following total thyroidectomy and radioiodine ablation.However, limited data are available for patients treated with thyroid lobectomy.Methods: Patients who had lobectomy for papillary thyroid cancer followed for >1 year, withsufficient data on Tg and TgAb, including subgroup analysis for Hashimoto's thyroiditis andcontralateral nodules.Results: One-hundred sixty-seven patients met the inclusion criteria. Average tumor size was9.5 ± 6 mm. Following lobectomy, Tg was 12.1 ± 14.8 ng/mL. Of 52 patients with Hashimoto'sthyroiditis, 38% had positive TgAb with titers of 438 ± 528 IU/mL, and in patients withoutTgAb the mean Tg level was 14.7 ± 19.0 ng/mL. In 34 patients with contralateral nodules=1 cm, Tg was 15.3 ± 17 ng/mL. During the first 2 years of follow-up, Tg declined =1 ng/mLin 42% of patients (by 5.1 ± 3.7 ng/mL), remained stable in 22%, and increased in 36% (by4.9 ± 5.7 ng/mL). During a mean follow-up of 6.5 years (78 ± 43.5 months), 18 patients hadcompletion thyroidectomy and 12 were diagnosed with contralateral cancer (n = 8) or lymphnode metastases (n = 4). In patients with recurrence followed for >2 years, there was a rise inTg in 3 cases, Tg was stable in 2 cases, and in 1 TgAb decreased from 1534 to 276 IU/mL despitemetastatic lymph nodes. Basal Tg and Tg dynamics did not predict disease recurrence.Conclusions: Serum thyroglobulin used independently is of limited value for predicting ordetecting disease recurrence following thyroid lobectomy. Other potential roles of Tg, such asdetecting distant metastases following lobectomy, should be further studied.