Treatment of local and regional recurrences of differentiated thyroid cancer by radio-guided surgery with Iodine-131

Abstract

BACKGROUND/MATERIAL AND METHODS: The aim of this study was to assess the reliability of radioiodine (¹³¹I) and a gamma probe for radio-guided surgery (RGS) to detect and radically dissect lymph node recurrence (LNR) in 15 patients with differentiated thyroid cancer (DTC). The major inclusion criterion was the presence of a radioiodine-positive LNR after previous total thyroidectomy and at least two ineffective ¹³¹I treatments. The protocol was designed as follows: Day 0 - all patients were hospitalized and received 3.7 GBq of ¹³¹ I while clinically hypothyroid. Day 3 - pre-surgery whole-body scan with a therapeutic ¹³¹I dose (TxWBS) was acquired. Day 5 - neck surgery using a gamma probe (Navigator GPS, AutoSuture, Italy), recording the absolute counts and the lesion/background (L/B) counts ratio was performed. Day 7 - post-surgery TxWBS was performed using the remaining radioactivity.
RESULTS AND CONCLUSIONS: This protocol permitted us to identify neoplastic foci with high sensitivity and specificity, enabling us to remove lymph node metastases resistant to radioiodine therapy in a single session. The protocol also allowed detection of some additional tumoural foci in sclerotic areas or behind vascular structures that were not seen at the pre-surgery TxWBS evaluation.