Lymph node metastases from differentiated thyroid carcinoma: does radioiodine still play a role?

Ultrasonography and surgery have now become the elective diagnostic and therapeutic tools for neck lymph node (LN) metastases from differentiated thyroid carcinoma (DTC), reserving radioiodine therapy (RAI) for surgery failures. Aim of the present retrospective study was to evaluate results of RAI in cases of LN metastases displaying (131)I uptake over a long-term observation period and its possible role today.

From a series of 1276 patients who had undergone surgery for DTC, 130 cases were selected showing (131)I uptaking LN metastases, detected during follow-up scans and who were then submitted to surgery and/or RAI. Patients were divided into groups according both to extent of surgery, with/without lymphectomy, and to following treatment and outcome.

The initial surgical approach does not seem to significantly influence the outcome. (131)I therapy alone, sometimes at low doses, can be very effective in the management of LN metastases detected at Whole Body Scan, but multiple doses are often needed. The age at diagnosis is confirmed as a negative prognostic factor.

Considered radioprotection questions, RAI may solve (131)I uptaking LN metastases, above all if < 10 mm. For larger LN metastases and in the case of failure of RAI surgical excision is mandatory, while a subsequent therapeutic dose of (131)I could be useful to reveal incomplete excision.