125I radioactive seed localization (RSL) in surgery of cervical metastasis of thyroid cancer. / Localización con semillas radioactivas 125I (RSL) en cirugía de metástasis cervical de cáncer de tiroides.

ABSTRACT

INTRODUCTION: The aim of this work is the evaluation of usefulness of radioactive seed localization (RSL) for the detection of cervical recurrence of thyroid cancer in order to improve the surgical outcome. MATERIAL AND METHOD: Ten patients with thyroid cancer and lymph node involvement (4 naive and 6 with cervical recurrence) evidenced by ultrasound, cytology/Tg-FNAB (reoperated group) were selected for this procedure. A 125I seed was placed in the metastatic lesion using a needle guided by ultrasound. During surgery, a handheld gamma probe/portable gammacamera were used for lesion localization and excision. After removing the target tissue, it was verified that the seed was included in the excised tissue. Surgical intervention duration, lesion location, seed activity, thyroglobulin level, effective radiation dose, complications and the degree of surgical resection were analyzed. RESULTS: All the marked nodes were positive in histology. The mean duration of the ultrasound procedure was 11.4±3.4minutes. Seed was kept inside the patient, in average, during 4days (1-7) and the average surgical time was 44.7±29.1minutes. We found 21 metastatic specimens with an average diameter 13.9±6.3mm. The mean activity of the implanted seed was 71.27±21.6MBq (42.8-105) In the reoperated group, thyroglobulin level was 2.08±1.56ng/dl and decreased after surgery to 0.13±0.12ng/dl, P<.01. Only one case of transient hypoparathyroidism was found in the total group. CONCLUSIONS: The introduction of RSL in our unit has shown benefits for the patient and medical team, being a safe and effective procedure that also improves surgical programming.