MON-566 Early Diagnosis of Lymph Node Metastases by Serum Tg and Neck Ultrasonography, and Long Term Follow Up After Radioiodine and/or Surgical Treatment in Patients with Papillary or Follicular Thyroid Cancer.

We aimed to evaluate the early detection of metastatic lateral neck lymph nodes (LNL) in patients with papillary or follicular differentiated thyroid cancer (DTC), and long-term follow-up after I(131) and/or surgery. LNL evaluation has been made by thyroglobulin (Tg) measurement and neck ultrasonography (NU). We have enrolled 710 patients with DTC that previously underwent a near-total thyroidectomy and I(131) ablation of residual tissue, and a follow-up by Tg, NU, diagnostic and post-therapy whole body scan (WBS), alone or in combination. LNL were detected by TSH-stimulated Tg alone with a sensitivity of 86%, and a negative predictive value (NPV) of 84%; whereas NU had a sensitivity of 70%, and NPV of 68%. TSH-stimulated Tg plus NU increased the sensitivity to 98%, and of NPV to 96%. In patients with LNL uptaking radioiodine and then treated with I(131), the following outcomes were observed: 49% responded after a median of 4 cycles (median 354 mCi, cumulative dose; 7.4 years median follow-up) with “disappearence of uptake at post-therapy WBS and Tg<1 ng/ml” (complete remission, CR); 12% of not responding cases had CR following other treatments. Nine% of LNL patients not uptaking or not responder to I(131) were treated with surgery, and subsequent I(131) readministration with CR in 23% of cases (6.5 years median follow-up). In conclusion, an early detection of LNL in DTC-patients may be helpful to obtain a CR by I(131) in 49% after 4 or less I(131) treatments. A combination of different therapies could aid patients not responder/not uptaking I(131) to achieve a CR in 24% of cases.