Predictive role of nontumoral sodium iodide symporter activity and preoperative thyroid characteristics in remission process of thyroid cancer patients.

Abstract

OBJECTIVE:

The target of radioiodine ablation therapy (RIAT) after complete tumor removal is the nontumoral remnant tissue. We aimed to evaluate sodium iodide symporter (NIS) expression in nontumoral thyroid tissue in differentiated thyroid cancer (DTC) patients who have complete but delayed structural response (DSR) to RIAT after surgery. Preoperative thyroid characteristics such as volume and nontumoral histology were also investigated for both DSR and its control group as potential predictors of insufficient NIS activity in this study.

METHODS:

Total of 600 patients with postoperative remnant thyroid tissue and who were in remission after RIAT spontaneously, were included in the study. Patients with positive diagnostic whole body scan (DxWBS) with thyroid bed uptake and stimulated serum Tg level <2 ng/mL at first year visit after initial therapy were defined as DSR group. Immunohistochemical staining of NIS protein was performed on the nontumoral tissue sections from surgery and semi quantified in terms of density and intensity. DSR and its control group were also compared in terms of NIS expression, radioiodine (RAI) uptake on post-therapy scan and preoperative thyroid characteristics.

RESULTS:

When compared with the control group, the density and intensity of NIS expression as well as the intensity of RAI uptake were significantly lower in DSR group (p = 0.001). There were also significant differences between groups regarding preoperative thyroid characteristics; i.e. preoperative thyroid volumes were significantly higher and the presence of concurrent benign thyroid disease was significantly more common in DSR group (p = 0.035, p = 0.001). Hashimoto thyroiditis was 8.59 times higher (95% CI; 2.31-31.96) and multinodular goiter was 7.50 times higher (95% CI; 1.88-29.91) among DSR group when compared with the control group.

CONCLUSIONS:

Our findings suggest that insufficient NIS activity in nontumoral thyroid tissue associates with DSR in DTC patients who have postoperative remnant tissue. Preoperative thyroid characteristics such as volume and concomitant benign thyroid disease may have an important role in predicting the complete response time to RIAT in these patients.

• Authors: Nilufer Yildirim-Poyraz, Aylin Yazgan, Elif Ozdemir, Aysegul Gozalan, Mutlay Keskin, Reyhan Ersoy, Seyda Turkolmez, Bekir Cakir
• Journal: Annals of nuclear medicine (Ann Nucl Med) Vol. 28 Issue 7 Pg. 623-31 (Aug 2014) ISSN: 1864-6433 [Electronic] Japan
• PMID: 24823701 (Publication Type: Journal Article)

Chemical References

• Iodine Radioisotopes
• Symporters
• sodium-iodide symporter

Topics

• Ablation Techniques
• Adolescent
• Adult
• Aged
• Aged, 80 and over
• Female
• Humans
• Iodine Radioisotopes (therapeutic use)
• Male
• Middle Aged
• Preoperative Period
• Symporters (metabolism)
• Thyroid Gland (metabolism, pathology, surgery)
• Thyroid Neoplasms (metabolism, pathology, surgery, therapy)
• Young Adult