Premium
Bexarotene‐induced hypothyroidism: Characteristics and therapeutic strategies
Author(s) -
Makita Noriko,
Manaka Katsunori,
Sato Junichiro,
Mitani Koji,
Nangaku Masaomi,
Iiri Taroh
Publication year - 2019
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/cen.13975
Subject(s) - bexarotene , medicine , levothyroxine , endocrinology , gastroenterology , thyroid function , adverse effect , chemotherapy , concomitant , thyroid function tests , thyroid , biology , biochemistry , nuclear receptor , transcription factor , gene
Summary Objective Central hypothyroidism (CH) is a well‐known adverse effect of bexarotene treatment for cutaneous T‐cell lymphoma (CTCL). While concomitant levothyroxine therapy is recommended in these cases, associations between ethnic variation or susceptibility and bexarotene‐induced CH have not yet been reported. This study aimed to characterize the kinetics and dose dependency of bexarotene‐induced CH in Japanese patients. Design and patients Sixty‐six Japanese patients with CTCL were retrospectively investigated by evaluating thyroid function during the early phase of bexarotene therapy. Results At one week after bexarotene initiation, TSH and FT4 values significantly declined. However, this effect was not bexarotene dose‐dependent at least at the dose of 96‐320 mg/m 2 . Approximately 1 month later, 61 patients exhibited hypothyroidism at a relatively low dose of bexarotene (average 251 mg/m 2 /day). Forty‐five study cases showed this effect at 1 week. Simple regression analyses indicated that higher pretreatment TSH values (at a cut‐off value of 1.30:73% sensitivity, 57% specificity) or lower normal (within the lower half of the reference range) pretreatment FT4 values (84% sensitivity, 57% specificity) were predictive of hypothyroidism at 1 week. The remaining 21 cases showed euthyroidism at 1 week, at which TSH values may roughly predict their thyroid function at 1 month (at a cut‐off value of 0.05:100% sensitivity, 80% specificity). Conclusions Preventive treatment with levothyroxine is recommended for Japanese CTCL patients prior to bexarotene therapy. Minimally, it should be considered for patients with a pretreatment TSH above 1.30, a lower normal pretreatment FT4, or a TSH below 0.05 at 1 week.