COMBINATION OF RADIOIODINE (I-131) AND PROBE-GUIDED SURGERY FOR PERSISTENT OR RECURRENT THYROID-CARCINOMA

To improve the completeness of surgical excision of persistent or recu rrent differentiated thyroid carcinoma, the following protocol was use d for the treatment of 54 patients with functioning lymph node metasta ses: administration of 3.7 gigabecquerels (100 mCi) I-131; total body scintigraphy (TBS) on day 4; surgery on day 5, using an intraoperative probe (Gammed 2, Eurorad); and postoperative TBS with the remaining I -131 activity on day 7. The 54 patients (35 women and 19 men presentin g 47 papillary carcinomas, 2 well differentiated follicular carcinomas , and 5 poorly differentiated follicular carcinomas) had already under gone surgery for differentiated thyroid carcinoma: total thyroidectomy (51 patients) or lobectomy with isthmusectomy (3 patients), with lymp h node dissection in 33. One to 7 131I treatments were performed befor e inclusion. Preoperative I-131-TBS with a high dose of I-131 allowed accurate localization of previously suspected neoplastic foci and dete ction of yet unknown foci in 56%; it was the most sensitive tool for l ocalizing neoplastic foci. The use of an intraoperative probe was cons idered decisive in 20 patients, as neoplastic foci were found inside s clerosis due to previous surgery (n = 9), at unusual sites behind vess els or in the mediastinum (n = 10), or both (n = 1). In 26 patients, i t facilitated the preoperative detection of foci with I-131 uptake alr eady depicted at preoperative I-131-TBS. In all 46 patients, the compl eteness of excision was demonstrated by both the probe and the postope rative 131I-TBS and was confirmed during follow-up. Of note, lymph nod e metastases undetected by I-131-TBS or by the probe were found in 14 patients at histological examination. This clearly shows that en block dissection is the only recommended procedure. In four patients, no ne oplastic foci were found and in four patients, uptake was either due t o the thymus (in two) or to the salivary glands (in two).