Differentiated Thyroid Cancer lymph-node relapse. Role of adjuvant radioactive iodine therapy after lymphadenectomy

Eur J Nucl Med Mol Imaging. 2017 Jun;44(6):926-934. doi: 10.1007/s00259-016-3593-0. Epub 2016 Dec 14.


Purpose: Our purpose as to evaluate the impact of adjuvant radioactive iodine therapy (RAI) on prognosis, as assessed by progression-free survival (PFS) and overall survival (OS), in patients affected by differentiated thyroid carcinoma (DTC) lymph-node relapse and previously treated with lymphadenectomy.

Methods: We retrospectively evaluated DTC patients treated with lymph-node dissection for disease relapse. All patients had previously undergone total thyroidectomy and radioiodine remnant ablation (RRA). We used clinical and histological data obtained during follow-up to assess response and outcome. By means of univariate and multivariate time-to-event analyses, we assessed the impact of RAI on outcome (PFS and OS) and the prognostic role of thyroglobulin (Tg) levels under suppression with levothyroxine (Tg-on) measured 1-3 months after lymphadenectomy and of other risk factors.

Results: We evaluated 113 patients (age at diagnosis: median 41 years, interquartile range: 31-59), 64 of whom were treated with RAI. Over a median follow-up time of 5.7 years, 27 patients showed disease progression and 13 died. Kaplan-Meier PFS and OS curves showed that age on diagnosis, tumor histology, tumor size, DTC aggressive variant, and Tg-on were associated with prognosis. Patients with Tg-on ≥1 ng/ml treated with RAI showed a better PFS (Log-rank pp 0.001) and OS (p = 0.005) than untreated patients, while no effect of RAI was observed in patients with Tg-on <1 ng/ml. Multivariate models showed that age, Tg-on (≥1 vs. < 1 ng/ml, HR: 18.2, 95% CI: 5.09-64.8, p = 0.001) and RAI (Yes vs. No, HR: 0.36,95%CI: 0.15-0. 9, p = 0.02) remained the only independent factors associated with PFS, but only age and Tg-on remained significantly associated with OS (HR: 8.31, 95%CI:1.56-44.3, p = 0.01). Nonetheless, patients treated with RAI showed a lower risk of mortality (HR: 0.34, 95%CI: 0.1-1.15 p = 0.08) than untreated patients.

Conclusions: RAI after lymphadenectomy for DTC relapse is significantly associated with better PFS only in patients with Tg-on ≥1 ng/ml.

Keywords: Adjuvant RAI; Differentiated thyroid cancer; Lymphadenectomy; Prognosis.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Child
  • Disease-Free Survival
  • Female
  • Humans
  • Iodine Radioisotopes / therapeutic use*
  • Lymphatic Metastasis
  • Male
  • Middle Aged
  • Radiotherapy, Adjuvant
  • Recurrence
  • Retrospective Studies
  • Thyroid Neoplasms / pathology*
  • Thyroid Neoplasms / radiotherapy*
  • Thyroid Neoplasms / surgery
  • Thyroidectomy*
  • Young Adult


  • Iodine Radioisotopes