Abstract
Introduction Differentiated thyroid carcinoma (DTC) has increased incidence. Intermediate- and
high-risk patients have lymph node relapse rate ranging from 10 to 50%, and receive
multiple reinterventions, increasing the morbidity of the disease. Currently, there
are no established guidelines for the use of second radioactive iodine (RAI) therapy
after the reintervention for local recurrence.
Materials and Methods This is a retrospective review of the medical records of 1,299 patients treated from
January 2016 to July 2019 with DTC. We included 48 patients who received total thyroidectomy,
RAI remnant ablation, surgery to remove the locally recurrent/persistent papillary
thyroid carcinoma (PTC), and received a second RAI therapy.
Results There were no significant differences between thyroglobulin (Tg) levels before reoperation
(Tg0), Tg levels postoperatively (Tg1), and Tg levels after 6 months of second adjuvant
RAI therapy (Tg2). However, we evidenced a 69.79% drop in first Tg levels (Tg0: 24.7
vs. Tg1: 7.56, p=0.851) and 44.4% decrease in second Tg levels (Tg1: 7.56 vs. Tg2: 4.20, p=0.544). Also, 77.1% of the patients did not have another documented recurrence. The
median relapse-free time was 10.9 months (range: 1.3–58.2 months).
Conclusion The results of the study cannot assess that a second RAI treatment after reoperation
for locoregionally persistent or recurrent disease have a significant impact on treatment
outcomes in intermediate- or high-risk patients with PTC. However, the 77.1% of patients
have not presented a second documented recurrence and the median values of Tg and
TgAb levels showed a substantial decrease after surgery and second RAI treatment.
Keywords
thyroid cancer - local neoplasm recurrence - thyroglobulin - nuclear medicine - iodine
- reoperation
