Scientific publications
The placebo effect in thyroid cancer: a meta-analysis
Llavero-Valero M (1), Guillén-Grima F (2), Zafon C (3), Galofré JC (4).
(1) M Llavero-Valero, Endocrinology and Nutrition, Clínica Universidad de Navarra. University of Navarra, Pamplona, Spain.
(2) F Guillén-Grima, Department of Preventive Medicine, Clínica Universidad de Navarra. University of Navarra., Pamplona, 31008, Spain.
(3) C Zafon, Endocrinology, Hospital Universitari Vall d'Hebron, Barcelona, Spain.
(4) J Galofré, Endocrinology and Nutrition, Clínica Universidad de Navarra. University of Navarra, Pamplona, Spain
CONTEXT
The natural history of advanced thyroid malignancies is largely unknown. The outcome of patients included in the placebo arm of clinical trials could be reflective of their therapy-free evolution.
OBJECTIVE
To analyze the response rate, symptoms and adverse effects of locally advanced or metastatic differentiated (DTC) and medullary thyroid cancer (MTC) in patients treated with placebo in clinical trials.
DESIGN
PubMed (MEDLINE) and SCOPUS databases were searched through September 2015 to identify high quality randomized controlled clinical trials. We included studies that recruited patients with DTC or MTC with a placebo arm.
METHODS
We conducted a meta-analysis for each category of response rate, adherence to treatment, and adverse events. An empirical Bayesian random-effect model was used.
RESULTS
We identified five clinical trials. DTC and MTC were independently analyzed. In the placebo arm no complete response was observed; partial response occurred in 1.6% (0.6-3) and 6.4% (3.4-10.3) of DTC and MTC, respectively; stable disease was described in 40.5% (34.6-46.9) and 53.9% (44.3-64.4) of DTC and MTC, respectively. DTC reached a disease control rate of 42.3% (36.2-48.9) and MTC of 60.2 (50.1-71.4). Treatment discontinuation rate was 3.5% (1.9-5.5) in DTC and 5.7% (3.0-9.4) in MTC. Rate of dose reduction was 7.3% (4.8-10.5) in DTC and 6.2% (3.3-10.0) in MTC.
CONCLUSIONS
This meta-analysis provides extensive data on the response rate and adverse effects of locally advanced or metastatic DTC and MTC in patients treated with placebo. These results may be used for comparisons with results from clinical trials without placebo arm.
CITATION Eur J Endocrinol. 2016 Jan 13. pii: EJE-15-1119
