Delayed TSH recovery after dose adjustment during TSH-suppressive levothyroxine therapy of thyroid cancer

[helvella]

Another paper pulling the rug from under TSH - at least in a limited circumstance.

I doubt that the mention of cancer is at all relevant except as to why the patients were on TSH-suppressive doses of levothyroxine. Surely it is likely to be the same even if it had simply been over-medication howsoever caused?

Of course, many here would question whether TSH can ever be used to manage levothyroxine dosing.

Clin Endocrinol (Oxf). 2017 Apr 4. doi: 10.1111/cen.13344. [Epub ahead of print]

Delayed TSH recovery after dose adjustment during TSH-suppressive levothyroxine therapy of thyroid cancer.

Kim HI1, Kim TH1, Kim H1, Kim YN1, Jang HW2, Kim JH3, Hur KY1, Chung JH1, Kim SW1.

Author information

1 Division of Endocrinology & Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul.

2 Department of Medical Education, Sungkyunkwan University School of Medicine, Seoul.

3 Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul.

Abstract

BACKGROUND:

Delayed thyroid-stimulating hormone (TSH) recovery during treatment of Graves' disease is caused by long-term excessive thyroid hormone, which results in down-regulation of pituitary thyrotropes. However, it is unknown whether delayed TSH recovery exists after levothyroxine (LT4) dose reduction in differentiated thyroid cancer (DTC) patients after long-term TSH suppression.

METHODS:

We retrospectively reviewed 97 DTC patients with LT4 dose reduction after long-term TSH suppression. TSH levels at baseline (point 1), 6 months (point 2), and 12-18 months (point 3) after LT4 dose reduction were compared. A delayed TSH recovery group whose TSH levels changed to upper target TSH category (2015 revised ATA guidelines) from points 2 to point 3 was identified and risk factors were analyzed.

RESULTS:

The median TSH level at point 3 was significantly higher than that of point 2 (0.17 vs. 0.09 mIU/L; P <0.001). The delayed TSH recovery group (44.3%) showed increased body weight (60.84 vs. 62.73 kg; P = 0.01) while normal response group did not. Greater reduction (%) in the LT4 dose per weight [HR 1.10, 95% CI (1.00-1.22), P = 0.04], higher BMI before thyroid surgery [1.19, 1.03-1.38, P = 0.01] predicted the occurrence of delayed TSH recovery while higher dose of LT4 per weight after reduction showed preventive effect [HR 0.01, 95% CI (0.00-0.54); P = 0.02].

CONCLUSIONS:

Delayed TSH recovery was common during LT4 dose reduction after long-term TSH suppression for DTC management. Six months may not be enough for TSH recovery and to evaluate thyroid hormone status by serum TSH. This article is protected by copyright. All rights reserved.

This article is protected by copyright. All rights reserved.

KEYWORDS:

Key terms; Thyrotropin; delayed recovery; dynamic risk stratification; thyroid cancer

PMID: 28375573

DOI: 10.1111/cen.13344

ncbi.nlm.nih.gov/pubmed/283...

[Clutter]

Helvella,

2 dose reductions in 2015 didn't shift my TSH up and a further dose reduction in May last year didn't budge it up after six weeks. FT4 and FT3 dropped after each reduction. I'm having my annual TFT tomorrow but I doubt TSH will have gone up.

[shaws Administrator]

Thank you for another good post.