One-year Thyroglobulin Levels as a Predictive Measure for Recurrence and Need for Continued Surveillance in Treated Differentiated Thyroid Cancer.

PURPOSE: Patients with differentiated thyroid cancer (DTC) undergo posttreatment surveillance for several years. We aim to better define an excellent response to therapy using thyroglobulin (TG) and thyroglobulin antibody (TGab) levels at 1-year to tailor appropriate length of surveillance. METHODS: Patients with DTC who underwent surgical treatment with or without adjuvant radioiodine therapy were followed with standard American Thyroid Association surveillance. TG and TGab levels at 1-year posttreatment were used to define 3 cohorts: undetectable TG (<0.5 ng/mL), detectable TG (≥0.5 ng/mL), and positive TGab (>1 IU/mL). The rates of structural recurrence and the trends of TG and TGab were compared. RESULTS: Of the 268 study patients at 1-year, 210 (78%) had undetectable TG, 29 (11%) had detectable TG, and 29 (11%) had positive TGab. The overall structural recurrence rate was 18/268 (7%): undetectable TG at 1 year, 3/210 (1%), detectable TG at 1-year, 11/29 (38%), and positive TGab at 1-year, 4/29 (13%). At the last follow-up, 196/210 (93%) patients with undetectable TG at 1-year continued to have undetectable TG levels. Regarding patients with detectable TG at 1-year, in 11/29 (38%), detectable TG was converted to undetectable TG at the last follow-up without additional treatments. Of those with positive TGab at 1 year, 6/29 (21%) had resolution of TGab and undetectable TG levels at the last follow-up without additional treatments. CONCLUSION: One year after treatment of DTC, TG levels <0.5 ng/mL, in the absence of TGab, are associated with an exceedingly low risk of recurrence suggesting that further surveillance may not be warranted.

Reoperative lymph node dissection for recurrent papillary thyroid cancer and effect on serum thyroglobulin.

BACKGROUND: Papillary thyroid cancer (PTC) has an excellent prognosis with current treatment methods. However, the rates of locoregional recurrence after initial surgical management remain significant. This study evaluates the effect of reoperative neck dissection for locoregional recurrence of PTC after initial total thyroidectomy and radioiodine therapy on the incidence of cervical recurrence and postoperative serum thyroglobulin (Tg) levels. METHODS: This is a retrospective cohort study conducted in a single academic medical center of patients with recurrent or persistent PTC isolated to the neck after previous total thyroidectomy with or without lymph node dissection and adjuvant I(131) therapy who were treated with reoperative lymph node dissection. Outcomes including operative complications, pathologic findings, and effect of surgery on Tg levels and rates of recurrent disease were analyzed. RESULTS: From 2001 to 2010, a total of 61 patients had reoperative neck dissections for recurrent cervical PTC with a complication rate of 5 %. Seventy-two percent of patients were clinically free of detectable disease, and 28 % of patients had recurrent, persistent, or newly metastatic disease detected during the follow-up period. All patients had significant decreases in Tg levels, with a median 98 % reduction in preoperative levels. However, only 21 % of patients had an undetectable stimulated Tg (<0.5 ng/mL) during the follow-up period of 15.5 months. CONCLUSIONS: Reoperative treatment of recurrent or persistent PTC can be performed with low complication rates, and Tg levels greatly decrease in most patients; however, few achieve undetectable stimulated Tg.