Quality of life comparison in thyroxine hormone withdrawal versus triiodothyronine supplementation prior to radioiodine ablation in differentiated thyroid carcinoma: a prospective cohort study in the Indian population

BACKGROUND

Thyroid withdrawal in preparation for radioiodine ablation (RIA) may have a profound impact on health-related quality of life (HRQL). Cost implications and scheduling limit the use of recombinant TSH and triiodothyronine (T3) with its shorter half-life is a conceptually attractive alternative.

METHODS

Prospective cohort study design with patients having withdrawal of thyroxine (n = 37) or T3 supplementation (n = 33). HRQL was assessed using EORTC QLQ-C30, QLQ-H&N35 and modified Billewicz questionnaires. Time interval to achieve optimal TSH levels (at least 30 mIU/ml) prior to RIA was determined.

RESULTS

With the exception of emotional domain (QLQ-C30 p = 0.045), LT3 supplementation did not confer significant benefit when compared to LT4 withdrawal. Target serum TSH levels was achieved in 95% of patients by week 4 post thyroidectomy.

CONCLUSIONS

LT3 supplementation delivered equivocal benefit and therefore the alternate strategies to minimize the impact on HRQL of reduction in the duration of hypothyroidism in T4 withdrawal are suggested.

Change of Therapeutic Response Classification According to Recombinant Human Thyrotropin-Stimulated Thyroglobulin Measured at Different Time Points in Papillary Thyroid Carcinoma

Purpose

We investigated whether response classification after total thyroidectomy and radioactive iodine (RAI) therapy could be affected by serum levels of recombinant human thyrotropin (rhTSH)-stimulated thyroglobulin (Tg) measured at different time points in a follow-up of patients with papillary thyroid carcinoma (PTC).

Methods

A total of 147 PTC patients underwent serum Tg measurement for response assessment 6 to 24 months after the first RAI therapy. Serum Tg levels were measured at 24 h (D1Tg) and 48-72 h (D2-3Tg) after the 2^nd injection of rhTSH. Responses were classified into three categories based on serum Tg corresponding to the excellent response (ER-Tg), indeterminate response (IR-Tg), and biochemical incomplete response (BIR-Tg). The distribution pattern of response classification based on serum Tg at different time points (D1Tg vs. D2-3Tg) was compared.

Results

Serum D2-3Tg level was higher than D1Tg level (0.339 ng/mL vs. 0.239 ng/mL, P < 0.001). The distribution of response categories was not significantly different between D1Tg-based and D2-3Tg-based classification. However, 8 of 103 (7.8%) patients and 3 of 40 (7.5%) patients initially categorized as ER-Tg and IR-Tg based on D1Tg, respectively, were reclassified to IR-Tg and BIR-Tg based on D2-3Tg, respectively. The optimal cutoff values of D1Tg for the change of response categories were 0.557 ng/mL (from ER-Tg to IR-Tg) and 6.845 ng/mL (from IR-Tg to BIR-Tg).

Conclusion

D1Tg measurement was sufficient to assess the therapeutic response in most patients with low level of D1Tg. Nevertheless, D2-3Tg measurement was still necessary in the patients with D1Tg higher than a certain level as response classification based on D2-3Tg could change.

Clinicopathologic risk factors of radioactive iodine therapy based on response assessment in patients with differentiated thyroid cancer: a multicenter retrospective cohort study

PURPOSE

We investigated whether predictive clinicopathologic factors can be affected by different response criteria and how the clinical usefulness of radioactive iodine (RAI) therapy should be evaluated considering variable factors in patients with differentiated thyroid carcinoma (DTC).

METHODS

A total of 1563 patients with DTC who underwent first RAI therapy after total or near total thyroidectomy were retrospectively enrolled from 25 hospitals. Response to therapy was evaluated with two different protocols based on combination of biochemical and imaging studies: (1) serum thyroglobulin (Tg) and neck ultrasonography (US) and (2) serum Tg, neck US, and radioiodine scan. The responses to therapy were classified into excellent and non-excellent or acceptable and non-acceptable to minimize the effect of non-specific imaging findings. We investigated which factors were associated with response to therapy depending on the follow-up protocols as well as response classifications. Multivariate logistic regression analysis was performed to identify factors significantly predicting response to therapy.

RESULTS

The proportion of patients in the excellent response group significantly decreased from 76.5 to 59.6% when radioiodine scan was added to the follow-up protocol (P < 0.001). Preparation method (recombinant human TSH vs. thyroid hormone withdrawal) was a significant factor for excellent response prediction evaluated with radioiodine scan (OR 2.129; 95% CI 1.687-2.685; P < 0.001) but was not for other types of response classifications. Administered RAI activity, which was classified as low (1.11 GBq) or high (3.7 GBq or higher), significantly predicted both excellent and acceptable responses regardless of the follow-up protocol.

CONCLUSIONS

The clinical impact of factors related to response prediction differed depending on the follow-up protocol or classification of response criteria. A high administered activity of RAI was a significant factor predicting a favorable response to therapy regardless of the follow-up protocol or classification of response criteria.

Long-term outcomes of renal function after radioactive iodine therapy for thyroid cancer according to preparation method: thyroid hormone withdrawal vs. recombinant human thyrotropin

PURPOSE

Long-term effects of iatrogenic hypothyroidism on renal function from thyroid hormone withdrawal during radioactive iodine therapy (RAIT) have not been studied, especially in subjects with mildly impaired renal function. We compared renal function in thyroid cancer subjects according to preparation method of either thyroid hormone withdrawal (THW) or injection of recombinant human thyrotropin (rhTSH).

METHODS

This retrospective study enrolled 241 thyroidectomized patients (rhTSH group, n = 87 and THW group, n = 154). Changes in glomerular filtration rate (GFR) were measured prior to surgery, at the time of RAIT, and during a regular follow-up at least one year after RAIT.

RESULTS

Baseline renal function was comparable between the rhTSH group and the THW group (91.4 mL/min/1.73 m² vs. 92.4 mL/min/1.73 m²). At the time of RAIT, GFR was significantly decreased in the THW group (70.6 mL/min/1.73 m², -23.6%), whereas renal function was preserved in the rhTSH group (85.4 mL/min/1.73 m², -6.6%). In the THW group, renal function was fully recovered within 6 months after RAIT and was maintained up to 24 months, even in subjects with baseline GFR less than 90 mL/min/1.73 m².

CONCLUSIONS

THW for RAIT preparation induced considerable reduction in renal function, but this change was transient. In contrast, injection of rhTSH did not decrease renal function, making it a good option for RAIT preparation for subjects with renal dysfunction.

Response Prediction of Altered Thyroglobulin Levels After Radioactive Iodine Therapy Aided by Recombinant Human Thyrotropin in Patients with Differentiated Thyroid Cancer

Purpose

Thyroglobulin (Tg) may be released from damaged residual thyroid tissues after radioactive iodine (RAI) therapy in patients with differentiated thyroid carcinoma (DTC). We investigated whether altered levels of serum Tg after recombinant human thyrotropin (rhTSH)-aided RAI therapy could be a prognostic marker in patients with DTC.

Methods

We evaluated 68 patients who underwent RAI therapy after total thyroidectomy. Serum Tg levels were measured just before RAI administration (D0Tg) and 7 days after RAI therapy (D7Tg). Patients with a D0Tg level greater than 2.0 ng/mL were excluded to more precisely evaluate the injury effect of RAI in small remnant tissues. The ratioTg was defined as the D7Tg level divided by that on D0Tg. The therapeutic responses were classified as acceptable or non-acceptable. Finally, we investigated which clinicopathologic parameters were associated with therapeutic response.

Results

At the follow-up examination, an acceptable response was observed in 50 patients (73.5%). Univariate analysis revealed significant differences in N stage (P = 0.003) and ratioTg (acceptable vs. non-acceptable responses, 21.9 ± 33.6 vs. 3.8 ± 6.5; P = 0.006). In multivariate analysis, only ratioTg significantly predicted an acceptable response (odds ratio 1.104; 95% confidence interval 1.005-1.213; P = 0.040). A ratioTg above 3.5 predicted an acceptable response with a sensitivity of 66.0%, specificity of 83.3%, and accuracy of 70.6% (area under the curve = 0.718; P = 0.006).

Conclusions

Altered levels of serum Tg after RAI therapy, calculated as the ratioTg (D7Tg/D0Tg), significantly predicted an acceptable response in patients with DTC.

Early stimulated thyroglobulin for response prediction after recombinant human thyrotropin-aided radioiodine therapy

OBJECTIVE

Measurement of recombinant human thyrotropin (rhTSH)-stimulated thyroglobulin (Tg) is generally recommended 72 h after the second rhTSH injection. However, due to the acute effect of I-131 on thyrocytes, Tg measured after radioiodine therapy (RIT) would not accurately reflect the thyroid tissue burden. We aimed to determine predictive values of serum Tg level measured just before rhTSH-aided RIT and to compare the results obtained just after RIT in patients with differentiated thyroid carcinoma (DTC).

METHODS

We evaluated 150 patients with DTC who underwent rhTSH-aided RIT (2.96-6.66 GBq) after total thyroidectomy between 2009 and 2014. Serum Tg level was measured 24 h (early Tg) and 72 (or 96) h (delayed Tg) after the second rhTSH injection. An excellent response was defined based on the latest American Thyroid Association Guidelines. Univariate and multivariate analyses were performed for early Tg, delayed Tg, and other clinical variables.

RESULTS

In the multivariate analysis, tumor size [odds ratio (OR) 1.716; 95% confidence interval (CI) 1.019-2.882; p = 0.042] and early Tg level (OR 2.012; 95% CI 1.384-2.925, p < 0.001) independently predicted excellent responses. The cutoff for the best early Tg level to predict a non-excellent response was 2.0 ng/mL. Delayed Tg was not a significant predictor (OR 0.992; 95% CI 0.969-1.015; p = 0.492).

CONCLUSIONS

Early stimulated Tg significantly predicted therapeutic response after rhTSH-aided RIT in patients with DTC. Therefore, serum Tg should be measured before RIT to predict therapeutic responses.

Rhabdomyolysis in the setting of induced hypothyroidism and statin therapy: a case report

Mild elevation of creatine kinase (CK) is common in untreated hypothyroidism, but severe myositis and overt rhabdomyolysis are rare. Similarly, muscle pain and CK elevation are potential side effects of statin therapy, yet rhabdomyolysis is likewise rare in the absence of medication interactions adversely affecting statin metabolism. The coexistence of statin therapy and hypothyroid states may synergistically increase the risk of myopathy. We describe a case of rhabdomyolysis attributable to induced hypothyroidism in a patient on chronic statin medication who was anticipating adjuvant radioiodine ((131)I) therapy for a thyroid carcinoma.

Recombinant human thyrotropin use resulting in ovarian hyperstimulation: an unusual side effect

A 43-year-old female was administered recombinant human thyrotropin-α (Thyrogen®; Genzyme Corp., Cambridge, Mass., USA) before a fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) scan as part of an evaluation of thyroid cancer recurrence. She was administered two doses of Thyrogen only 4 weeks before for stimulated thyroglobulin measurement. The PET/CT scan demonstrated enlarged ovaries which on subsequent conservative follow-up resolved. This transient hyperstimulated state of the ovaries was presumed to be related to Thyrogen injections received twice within a space of a month. Thyrogen is being increasingly used for raising the level of thyroid-stimulating hormone (TSH), besides thyroid hormone withdrawal for suspected recurrence of differentiated thyroid carcinoma. Ovarian hyperstimulation has been reported as an iatrogenic complication for in vitro fertilization with the presence of human chorionic gonadotropin being invariably associated. Transient gestational thyrotoxicosis has been reported to be related to promiscuous activation of the thyrotropin receptor by chorionic gonadotropin. In our case it is possible that due to the promiscuous stimulation, thyrotropin caused a follicle-stimulating hormone (FSH)-like action resulting in ovarian hyperstimulation. The reason behind this could be the shared sequence identity of the hormone-binding domains of TSH and FSH receptors, or some mutation in the FSH receptor. In conclusion, our case highlights a potential side effect of administering Thyrogen in females of the reproductive age group.

A placebo-controlled, blinded and randomised study on the effects of recombinant human thyrotropin on quality of life in the treatment of thyroid cancer

BACKGROUND

It is well known that thyroid hormone withdrawal (THW) in thyroid cancer patients can induce a decrease in quality of life (QOL). Recombinant human thyrotropin (rh-TSH) has been used to avoid this; however, no blinded studies have ever documented the effect.

OBJECTIVE

To compare QOL in patients with differentiated thyroid cancer (DTC) treated with either rh-TSH or liothyronine (L-T3) THW for 10 days.

STUDY DESIGN

Double-blind, randomised cross-over.

PATIENTS

Fifty-six patients with DTC treated by total thyroidectomy and indication for postsurgery radioiodine (RI) ablation therapy.

INTERVENTION

Randomisation to either L-T3 and rh-TSH prior to the first RI course and following this to ingest placebo tablets and receive placebo injections before a second RI uptake measurement 4-6 months later, or to receive placebo before the primary RI ablation and active therapy 4-6 months later.

MAIN OUTCOME MEASURES

QOL was measured by SF-36 and 2 visual analogue scale (VAS) scores at baseline and during RI therapy or RI uptake.

RESULTS

A significant difference in QOL was seen in 2 of 4 predefined SF-36 domains (7.2 and 6.6%) and 2 VAS scales (10 and 14%), favouring rh-TSH therapy.

CONCLUSION

This is the first blinded randomised clinical trial describing the effect of rh-TSH compared to L-T3 THW on QOL in DTC patients. A significant difference was demonstrated, though smaller than described in previous non-blinded studies.

Role of Recombinant Human Thyrotropin (rhTSH) in the Treatment of Well-Differentiated Thyroid Cancer

Since the introduction of radioiodine (RAI) for treatment of well-differentiated thyroid cancer (DTC) more than 50 years ago, prolonged periods of hypothyroidism were routinely used as part of the treatment regimen. Recombinant human TSH (rhTSH) was introduced in the 1990s as a tool to elevate the serum TSH without the need for thyroid hormone withdrawal and symptomatic hypothyroidism. After being initially approved as a diagnostic tool for use in RAI scanning and stimulated thyroglobulin testing, rhTSH was approved as an adjunct to RAI remnant ablation in patients without distant metastases in Europe in 2005 and in the US in 2007. Following successful use of rhTSH for diagnostic purposes, it has been extensively studied for use with therapeutic doses of RAI in the setting of RAI remnant ablation and is now an integral part of DCT therapy. The use of rhTSH in clinical practice in the last decade was coupled with the growing interest in an individualized, risk-stratified approach to the management of patients with DCT. While traditional treatment for DTC included surgery and RAI therapy for all patients, many more recent studies demonstrated the value of selective use of RAI only in patients who will probably benefit from treatment. This manuscript reviews the evolving role of rhTSH in the current risk adapted climate of thyroid cancer management with particular emphasis on the use of rhTSH as an aid to RAI therapy.