Moderate thyroid hormone suppression therapy (THST) is associated with the best outcomes for patients with all stages of thyroid cancer, according to a prospective analysis of a multi-institutional registry published in the Journal of Clinical Endocrinology & Metabolism.
The researchers examined the outcomes of initial treatment for 4,941 patients with differentiated thyroid cancer (DTC), according to registry data from the National Thyroid Cancer Treatment Cooperative Study Group. The treatments included total/near total thyroidectomy (T/NTT), postoperative radioactive iodine-131 (131I), and THST. The median duration between treatment and follow-up for a patient was 6 years, with follow-up information available for all but 94 (1.9%) of the patients in the cohort.
Overall improvement was noted in stage III patients who received 131I (risk ratio, 0.66; P = .04) and stage IV patients who received both T/NTT and 131I (RR, 0.66; P = .049). In all stages, moderate THST was associated with significantly improved overall survival (RR stages I-IV: 0.13, 0.09, 0.13, and 0.33, respectively) and disease-free survival (DFS) (RR stages I-III: 0.52, 0.40, and 0.18, respectively); no additional survival benefit was achieved with more aggressive THST, even when distant metastatic disease was diagnosed during follow-up.
Lower initial stage and moderate THST were independent predictors of improved overall survival during follow-up years 1-3.
Consistent with previous research, this study also showed that T/NTT followed by 131I is associated with benefit in high-risk, but not low-risk patients.
“We report for the first time, in multivariate analysis of primary treatments for DTC, across all stages, only THST was associated with both improved stage-adjusted OS and DFS,” noted Dr. Aubrey A. Carhill and his colleagues.
“This analysis of the larger, more mature registry database extends and refines earlier observations regarding the impact of initial therapies on patient outcomes and further justifies the need for prospective, long-term, controlled studies,” the researchers noted.
Read the full study in the Journal of Clinical Endocrinology & Metabolism ( doi:10.1210/JC.2015-1346 ).