ECE2015 Eposter Presentations Thyroid cancer (90 abstracts)
The routine use of adjuvant RAI treatment in low-risk DTC remains controversial due to the lack of unequivocal evidences of its effectiveness in radically operated subjects. The aim of the study was a retrospective evaluation of long-term outcomes of combined DTC treatment to evaluate the impact of adjuvant RAI therapy in the low risk group. Primary hypothesis was: if adjuvant RAI treatment was unnecessary, a delay in RAI administration would have no impact on long-term outcomes.
Material and methods: The study group consisted of 510 DTC patients, staged pT1b-T4N0-N1M0. Total thyroidectomy was carried in all subjects and followed by RAI therapy. On the basis of initial DTC stage and postoperative stimulated serum thyroglobulin (Tg) level 272 patients were classified as a low risk group (T1T3, N0Nx and Tg <10 ng/ml), 90 as high risk (stimulated Tg >30 ng/ml), whereas 148 remaining constituted an intermediate risk group. Median follow-up was 12.1 years (range 1.515.2).
Results: To properly assess the efficacy of adjuvant RAI therapy all groups were divided depending on time of RAI administration. Next, subjects treated with RAI up 9 months after DTC diagnosis were compared to subgroups treated later: within 924 and >24 months. In the low risk group, patients treated with RAI up to 9 months, showed no recurrences, whereas among those, treated 924 months and >24 months after diagnosis, the risk of recurrence were 5.5 and 7.1%, respectively (P=0.035). There was no significant time depending difference in both intermediate and high risk groups.
Conclusion: Adjuvant RAI therapy, administered within a short time period after the operation significantly reduces the risk of cancer recurrence in the low advanced DTC. We believe that the exclusion of low risk patients from RAI therapy, suggested by the ATA and European guidelines, is not justified.