Impact of moderate vs stringent TSH suppression on survival in advanced differentiated thyroid carcinoma
Objectives To assess (i) the influence of Thyrotropin (TSH) suppression at a level of <0·1 mU/l and (ii) whether FT3 and FT4 levels have a prognostic significance independently of TSH values with regard to survival in patients with differentiated thyroid carcinoma (DTC) and distant metastases.
Patients and methods In a retrospective patient chart study, we reviewed survival in 157 DTC patients with distant metastases treated between September 1985 and 1 July 2010. Patients with at least three available FT3 and FT4 values during TSH suppression were eligible.
Results Fifty‐three of 157 patients died from DTC. DTC‐specific survival was significantly better in patients with a median TSH level ≤0·1 mU/l (median survival 15·8 years) than those with a non‐suppressed TSH level (median survival 7·1 years; P < 0·001). However, there was no further improvement in survival caused by TSH suppression to a level ≤0·03 mU/l (P = 0·24). FT3 and FT4 levels were also significantly associated with poorer survival; of these, only the prognostic value of FT3 was independent from that of TSH levels.
Conclusion The care of patients with DTC and distant metastases is like walking an endocrinological tightrope: non‐suppressed TSH levels, that is, >0·1 mU/l, are associated with an impaired prognosis. There is, however, no prognostic benefit from suppressing TSH to levels lower than 0·1 mU/l. On the contrary, an improvement in prognosis might be achieved by keeping FT3 levels as low as possible.
Document Type: Research Article
Affiliations: 1: Department of Nuclear Medicine 2: Comprehensive Cancer Center, University of Würzburg, Würzburg, Germany 3: Department of Endocrinology, University of Leiden, Leiden, The Netherlands
Publication date: April 1, 2012