The outcome of I-131 ablation therapy for intermediate and high-risk differentiated thyroid cancer using a strict definition of successful ablation.

Abstract

PURPOSE:

This article examines the outcome of radioactive iodine ablation therapy for thyroid cancer in high-risk patients and investigates background factors influencing ablation failure.

MATERIALS AND METHODS:

We included 91 patients in this retrospective analysis and evaluated the ablation success rate. Successful ablation was defined as the absence of visible iodine-131 (I-131) accumulation in the thyroid bed after whole-body scans and thyroglobulin levels <2 ng/ml in a TSH-stimulated state after ablation. We extracted data on patients' age, sex, I-131 dose, pathology, resection stump findings, tumor T category and thyroglobulin levels, which could affect ablation outcome.

RESULTS:

Successful ablation was achieved in only 14 patients (15.4%). Pre-ablation serum thyroglobulin levels were significantly higher in the ablation failure group than in the success group (P < 0.001), while no significant differences were found for other factors between the groups. Furthermore, thyroglobulin levels >10 ng/ml were significantly related to ablation failure after multivariate analysis (odds ratio 27.2; 95% confidence interval 2.469-299.7; P = 0.007).

CONCLUSION:

The ablation success rate was very low because of high thyroglobulin levels, even with high-dose I-131. High-risk patients, especially those with high thyroglobulin levels (>10 ng/ml), are unlikely to reach levels low enough to meet successful ablation criteria.

• Authors: Ken Watanabe, Mayuki Uchiyama, Kunihiko Fukuda
• Journal: Japanese journal of radiology (Jpn J Radiol) Vol. 35 Issue 9 Pg. 505-510 (Sep 2017) ISSN: 1867-108X [Electronic] Japan
• PMID: 28620714 (Publication Type: Journal Article)

Chemical References

• Iodine Radioisotopes
• Iodine-131

Topics

• Adult
• Aged
• Aged, 80 and over
• Female
• Humans
• Iodine Radioisotopes (therapeutic use)
• Male
• Middle Aged
• Radiosurgery (methods)
• Retrospective Studies
• Thyroid Neoplasms (surgery)
• Treatment Outcome
• Young Adult