Radioactive iodine ablation was not linked to improved 10-year survival outcomes in a cohort of patients with low-risk differentiated thyroid cancer, according to recent results.
The study was conducted because the American Thyroid Association and European Thyroid Association guidelines cannot recommend for or against radioactive iodine ablation after surgery in patients with low-risk differentiated thyroid cancer. The aim was to determine the survival benefit of radioactive iodine ablation in 1,298 patients with this cancer.
Eligible patients had been treated between 1975 and 2005. Outcomes included overall survival and disease-free survival according to radioactive iodine ablation.
The median follow-up duration was 10.3 years.
There were 911 patients who received radioactive iodine ablation after surgery vs. 387 patients who did not receive this treatment after surgery.
Univariate analysis results indicated that the 10-year overall survival was 94.6% in the ablation group and 95.8% in the non-ablation group (P=.006). Ten-year disease-free survival was 88.7% in the ablation group and 93.1% in the non-ablation group (P=.001).
Significant associations were observed between radioactive iodine ablation and all clinical factors, except sex.
Multivariate analysis results indicated no significant or independent link between overall survival and radioactive iodine ablation (P=.243). Similarly, no link was observed between ablation and disease-free survival (P=.2659).
Further stratification was conducted based on propensity score. Results of this Cox univariate analysis indicated that overall survival did not differ with ablation status (P=.3524), with an HR for radioactive iodine ablation of 0.75 (95% CI, 0.4-1.38). Results of the same analysis indicated that disease-free survival did not differ (P=.48), with a stratified univariate HR of 1.11 (95% CI, 0.73-1.7).
The researchers concluded that the study failed to prove any survival benefit of radioactive iodine ablation after surgery in patients with low-risk differentiated thyroid cancer.