The use of recombinant human TSH in a patient with metastatic follicular carcinoma and insufficient endogenous TSH production

Impact of age and sex on the quality of life following radioactive iodine ablation in patients with thyroid cancer

Purpose: We assessed patient discomfort and identified factors predictive of discomfort while receiving radioactive iodine (RAI) ablation.Methods: Between August 2015 and April 2016, 52 patients with differentiated thyroid cancer were enrolled in this study. All patients received recombinant human thyroid stimulating hormone (rhTSH) aided RAI ablation using 3.7 GBq or 5.55 GBq of RAI. Discomfort during their stay for RAI ablation was evaluated using a symptom questionnaire. We analyzed the relationship between the patient’s clinical data and the scores for the 15 items of the symptom questionnaire. We compared scores of questionnaires between male and female, under 45 years old and 45 and older, RAI activity of 3.7 GBq and 5.55 GBq. Also, scores of daily questionnaires were tested for differences.Results: Most patients did not have severe discomfort, but some patients had mild discomfort during their stay for RAI ablation, despite using rhTSH. Important determinants of discomfort were sex and age. Female patients reported more symptoms of fatigue, facial edema, cold intolerance, and nausea. Older patients (45 and older) complained of insomnia more often. However, the dose of RAI ablation (3.7 GBq vs 5.55 GBq) did not affect the scores of questionnaires.Conclusions: Sex and age were important predictors of patient’s discomfort during RAI ablation. Clinicians need to explain more about treatment and predicted discomforts to such patients before RAI ablation.

Analysis of Clinical Factors for the Determination of Optimal Serum Level of Thyrotropin After Recombinant Human Thyroid-Stimulating Hormone Administration

PURPOSE

To determine the optimal levels of thyroid-stimulating hormone (TSH) levels after administration of recombinant human TSH (rhTSH) to patients with differentiated thyroid cancer (DTC), we have analyzed the clinical parameters that affected the degree of the increase in serum levels of TSH.

METHODS

We retrospectively analyzed 276 patients with differentiated thyroid cancer (DTC), post-thyroidectomy and remnant ablation. Pearson's correlation coefficient test was used to evaluate the correlation between serum levels of TSH after rhTSH stimulation and various clinical factors, including age, sex, height, weight, body mass index (BMI), body surface area (BSA), serum blood urea nitrogen, creatinine, and estimated glomerular filtration rate (GFR). Linear regression analysis was used to determine the predictors of the degree of increase in serum TSH level after rhTSH stimulation.

RESULTS

After the rhTSH injections, all subjects achieved TSH levels of >30 μU/mL, with a mean of 203.8 ± 83.4 μU/mL. On univariate analysis, age (r = 0.255) and serum creatinine (r = 0.169) level were positive predictors for higher levels of serum TSH after rhTSH stimulation, while weight (r = -0.239), BMI (r = -0.223), BSA (r = -0.217), and estimated GFR (r = -0.199) were negative predictors. Multiple linear regression analysis revealed that serum creatinine was the most powerful independent predictor for serum levels of TSH, followed by age, BSA, and BMI.

CONCLUSIONS

An increment in serum TSH after rhTSH stimulation was significantly affected by age, BSA, BMI, and creatinine, with creatinine being the most powerful predictor. By understanding the difference in the increased levels of TSH in various subjects, their dose of rhTSH can be adjusted during scheduling for radioiodine ablation, or during follow-up (recurrence surveillance) after surgery and ablation.

Recombinant human thyrotropin (rhTSH) aided radioiodine treatment for residual or metastatic differentiated thyroid cancer

BACKGROUND

For patients with differentiated thyroid cancer (DTC) following thyroidectomy, thyroid hormone withdrawal (THW) for four to six weeks has been used for decades to increase serum thyroid-stimulating hormone (TSH) concentrations in order to enhance iodine-131 uptake by normal thyroid cells and differentiated thyroid tumour cells. Exogenous stimulation with recombinant human thyroid-stimulating hormone (rhTSH) offers an alternative to THW while avoiding the morbidity of hypothyroidism. However, the efficacy of rhTSH-aided iodine-131 treatment for residual or metastatic DTC has not been prospectively assessed.

OBJECTIVES

To assess the effects of rhTSH-aided radioiodine treatment for normal residual or metastatic DTC.

SEARCH STRATEGY

We obtained studies from computerised searches of MEDLINE, EMBASE and The Cochrane Library (all until November 2009), and paper collections of conferences held in Chinese.

SELECTION CRITERIA

Randomised controlled clinical trials and quasi-randomised controlled clinical trials comparing the effects of rhTSH with THW on iodine-131 treatment for residual or metastatic differentiated thyroid cancer with at least six months of follow up.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed risk of bias and extracted data.

MAIN RESULTS

Altogether 223 patients with DTC participated in four trials. Overall, studies had a high risk of bias. We found no statistically significant differences between rhTSH and THW treatment in terms of successful ablation rate but significant benefits in radiation exposure to blood and bone marrow. One trial reported on benefits in some domains of health-related quality of life. There were no deaths and no serious adverse effects in DTC patients treated with either rhTSH or THW. Maximum follow up was 12 months. None of the included trials investigated complete or partial remission of metastatic tumour, secondary malignancies or economic outcomes. We did not find sufficient data comparing rhTSH with THW-aided radioiodine treatment for metastatic DTC.

AUTHORS' CONCLUSIONS

Results from four randomised controlled clinical trials suggest that rhTSH is as effective as THW on iodine-131 thyroid remnant ablation, with limited data on significant benefits in decreased whole body radiation exposure and health-related quality of life. It is still uncertain whether lower iodine-131 doses (1110 MBq or 1850 MBq versus 3700 MBq) are equally effective for remnant ablation under rhTSH stimulation. Randomised controlled clinical trials are needed to guide treatment selection for metastatic differentiated thyroid cancer.

Radioiodine ablation of post-surgical thyroid remnants after preparation with recombinant human TSH: Why, how and when

AIMS

The use of recombinant human TSH (rhTSH) represents one of the most exciting innovations in the field of differentiated thyroid cancer (DTC) management, but the use of rhTSH for radioiodine post-surgical thyroid remnant ablation is still controversial. The aim of this review is to provide the reader with an analysis of the literature regarding the use of rhTSH for the radioiodine ablation of post-surgical thyroid remnants.

METHODS

We performed a literature search of the most relevant papers in the PubMed database.

FINDINGS AND CONCLUSIONS

To date, five prospective studies have been published regarding this topic and there is strong evidence of the effectiveness of rhTSH, at least when high doses of 131I are used. Vice-versa, data regarding the outcome of ablation using low doses (30 mCi) are quite different in the studies published. So the problem of the amount of 131I to be administered and the influence of iodine intake is still open. In fact, the results of some studies suggest that 131I uptake could be particularly dependent on iodine intake during the euthyroid state and when low doses of 131I are used. This could be the reason for the reduced radioiodine uptake observed in other studies. However, also when rhTSH stimulation had produced a reduced iodine uptake, this was at least partially compensated for by an increased half-time in thyroid cells. So rhTSH stimulation appears to have pathophysiological bases which all lead to a powerful destructive effect by 131I on thyroid cells. All the data in the literature appear concordant that rhTSH is safe and associated to a good quality of life and the problem of costs appears negligible when compared to the benefits for the patient. In most cases, the use of rhTSH, for radioiodine ablation of post-surgical thyroid remnants can represent the best therapeutic option that we can offer to the patient.

Comparison between remnant and red-marrow absorbed dose in thyroid cancer patients submitted to 131I ablative therapy after rh-TSH stimulation versus hypothyroidism induced by L-thyroxine withdrawal

OBJECTIVE

In thyroidectomized patients, increased levels of thyroid stimulating hormone (TSH) are necessary to maximize I uptake. Traditionally, this has been achieved by withdrawing L-thyroxine (L-T4) for 4-6 weeks, inducing hypothyroidism in patients. The availability of a genetically engineered version of the recombinant human TSH (rh-TSH) provides an alternative tool to enhance the TSH serum level without inducing hypothyroidism. In this paper the I remnant and red-marrow doses calculated in differentiated thyroid cancer (DTC) patients pre-treated with rh-TSH are compared to those calculated in patients in hypothyroidism induced by L-T4 withdrawal.

METHODS

Forty-six DTC patients, submitted to I ablative therapy, were randomly divided in group A (pre-treated with rh-TSH) and group B (treated after L-T4 withdrawal for 30 days). The red-marrow absorbed dose per unit administered activity and the remnant cumulated activity per unit administered activity were calculated for both groups.

RESULTS

The red-marrow dose in 17 rh-TSH treated patients is 0.06+/-0.02 mGy.MBq; that in 14 hypothyroid patients is 0.09+/-0.03 mGy.MBq (two-tailed unpaired t-test P=0.003). The remnant cumulated activity per unit administered activity in 10 rh-TSH treated patients is 0.9+/-0.8 h; that calculated in 21 hypothyroid patients is 1.55+/-1.05 h (two-tailed unpaired t-test P=0.063). This last result is mainly due to the difference between the maximum uptake (U) in rh-TSH (U=0.01+/-0.01) and hypothyroid patients (U=0.03+/-0.02) (two-tailed unpaired t-test P=0.019).

CONCLUSION

The rh-TSH pre-treated patients seem to have a lower uptake compared to those in hypothyroidism induced by L-T4 withdrawal. On the other hand their red-marrow absorbed dose seems to be lower.

Recombinant human thyrotropin-assisted radioiodine therapy for patients with metastatic thyroid cancer who could not elevate endogenous thyrotropin or be withdrawn from thyroxine

The value of recombinant human thyrotropin (rhTSH) as preparation for radioiodine therapy was assessed in 115 patients with metastatic thyroid cancer. Patients who were either unable to elevate endogenous TSH during thyroxine withdrawal, or in whom thyroxine withdrawal was contraindicated for medical reasons were eligible. Their physicians requested rhTSH as part of the Thyrogen Compassionate Use Program. This is a retrospective summary of the nonrandomized uncontrolled experience. We assessed the ability of rhTSH to elevate the serum TSH; to avoid the complications of hypothyroidism; to stimulate radioiodine uptake; and to stimulate the serum thyroglobulin. Disease response and adverse events were also assessed. After rhTSH, the serum TSH levels rose to >or=25mU/L in every patient in whom levels were measured (n = 112). Hypothyroid complications were avoided in 22 of 25 patients who had experienced them in the past, and in 47 of 51 patients who were at high risk for hypothyroid complications. Radioiodine uptake was present on whole-body scans (WBS) in 105 of the 115 patients. Serum thyroglobulin levels were lower than baseline in 73% of patients assessed at 12 months. Cancer-related symptoms were improved in approximately 25%. Two patients had serious adverse events that were thought to be related to rhTSH. rhTSH elevates serum TSH and facilitates radioiodine uptake in patients who cannot produce endogenous TSH or who cannot tolerate hypothyroidism.

Recombinant human thyrotropin is helpful in the follow-up and 131I therapy of patients with thyroid cancer: a report of the results and benefits using recombinant human thyrotropin in clinical routine

There is no doubt that the availability of recombinant human thyrotropin (rhTSH) is one of the milestones in the management of patients with differentiated thyroid cancer (DTC). It offers the opportunity to obtain representative serum thyroglobulin (Tg) levels and diagnostic whole-body scanning (Dx WBS) with 131I under adequate TSH elevation, while the patient continues to receive thyroid hormone. But rhTSH is also used with success in the treatment of local recurrences and distant metastases. In this retrospective analysis we were able to show that our excellent clinical experiences with the use of rhTSH (rare side effects and high compliance) could also be demonstrated by sufficiently elevated TSH levels and representative stimulated Tg measurements. Since April 2001 most of the patients with thyroid cancer in our hospital have undergone diagnostic examination (205 patients underwent 319 examinations) and 131I therapy (a total of 68 treatments) with rhTSH stimulation excluding the first radioiodine ablation of remnants after initial thyroidectomy. Our results show that under rhTSH stimulation 83.5% (diagnostic group) and 88% (therapy group) of our patients with DTC obtained a TSH level of greater than 80 mU/L after two injections of rhTSH (Thyrogen, Genzyme Corp., Cambridge, MA) 0.9 mg intramuscularly 24 hours and 48 hours before the administration of 131I. Only 2.3% (diagnostic group) and 0% (therapy group) demonstrated TSH levels less than 50 mU/L. Serum Tg levels under rhTSH-stimulated conditions showed that in 81.2% the serum Tg maximum was obtained on day 5. Because of the costs associated with periodically rhTSH-assisted Tg testing and based on the data of other studies we are now testing mainly on day 5 to identify residual tumor mass and to compare these Tg levels in the follow-up. Our experience demonstrates that the administration of rhTSH is a safe, effective, and-from an economic point of view- valuable tool in the management of patients with DTC.

Clinical uses of recombinant human thyrotropin

Recombinant human thyroid-stimulating hormone (rhTSH), used to enhance diagnostic radioiodine whole body scanning and thyroglobulin testing, has dramatically altered the management of patients with thyroid cancer. Withdrawal from thyroid hormone suppression therapy and subsequent hypothyroidism is no longer the only safe and effective method for thyroid cancer surveillance. Currently, rhTSH is only approved for the monitoring of low-risk patients with well-differentiated thyroid cancer and radioactive iodine administration, in selected cases. Additional applications of rhTSH include enhancing the sensitivity of positron emission tomography in thyroid cancer, the management of multinodular goiter, and dynamic testing of thyroid reserve. The diagnostic and therapeutic role of rhTSH in these areas is discussed in this review.

Uses for recombinant human TSH in patients with thyroid cancer and nodular goiter

Recombinant human TSH (rhTSH) has revolutionized the care of patients with differentiated thyroid cancer. Since its approval for clinical use in 2001 in Europe (1998 in the USA), rhTSH has greatly enhanced the surveillance of these patients by allowing the avoidance of hypothyroidism for TSH stimulation. Previously, a hypothyroid state was required for TSH stimulated diagnostic whole-body radio-iodine scans (DxWBS) and thyroglobulin (Tg) levels. Patients generally prefer rhTSH as a mechanism for TSH stimulation because symptoms of hypothyroidism can be completely avoided. Currently, rhTSH is only approved for diagnostic monitoring of differentiated thyroid cancer patients. There are many other potential uses for rhTSH, including facilitation of treatment of patients with thyroid cancer and nodular goiter. The diagnostic and therapeutic role of rhTSH in patients with differentiated thyroid cancer and nodular goiter will be discussed in this review.

Recombinant human thyroid-stimulating hormone: pharmacology, clinical applications and potential uses

The major functions of pituitary thyroid-stimulating hormone (TSH) are to maintain the biosynthesis and secretion of the thyroid hormones L-thyroxine (T4) and L-3,5,3'triidothyronine (T3). The TSH core contains two apoproteins, the alpha and beta subunits. The alpha subunit is identical to that of pituitary follitropin, pituitary lutropin and placental chorionic gonadotropin, whereas the beta subunit is unique. TSH is a glycoprotein; the glycoprotein components of the alpha and beta subunits account for more than 10% of their mass and are essential for normal thyrotropic action and intravascular kinetics. The hypothalamic tripeptide, TSH-releasing hormone (TRH) is required for optimum TSH biosynthesis, particularly as far as addition of the glycoprotein components is concerned. TRH deficiency is associated with secretion of TSH molecules that are appropriately measured in most assays but have reduced bioactivity. In previous years the TSH used in clinical practice was obtained and purified from bovine pituitaries. Bovine TSH was used to test thyroid function and to augment the uptake of radioiodine in patients with thyroid cancer. Bovine TSH has been largely abandoned as a clinical agent because of adverse immune reactions. A recombinant human TSH (rhTSH; Thyrogen), has been approved by the US FDA for diagnostic use in patients with thyroid cancer. The alpha and beta subunits of Thyrogen are identical to those of human pituitary TSH. Thyrogen has a specific activity of approximately 4 IU/mg and is a potent stimulator of T4, T3 and thyroglobulin (Tg) secretion in healthy volunteers. It also increases thyroid iodide uptake in patients with thyroid cancer or multinodular goitre and in volunteers, even those exposed to large amounts of stable iodide. Thyroid cancer patients who have been treated by thyroidectomy and radioiodine ablation but are at risk of harbouring residual thyroid cancer are candidates for Thyrogen administration to prepare them for whole body iodide scans and serum Tg measurements. In thyroidectomised thyroid cancer patients who are unable to secrete pituitary TSH upon thyroid hormone withdrawal, Thyrogen is the only acceptable method to prepare them for these procedures. Thyrogen has been used on a compassionate basis to prepare patients for radioiodine ablation. rhTSH, in addition to being useful in the management of patients with thyroid cancer, is potentially useful to test thyroid reserve and to aid in thyroid-related nuclear medicine procedures. In the future, TSH analogues that have superagonist or antagonist properties may become available as therapeutic agents.

Tumour dosimetry and response in patients with metastatic differentiated thyroid cancer using recombinant human thyrotropin before radioiodine therapy

The development of recombinant human thyrotropin (rhTSH) has given clinicians new options for diagnostic follow-up and treatment of patients with differentiated thyroid cancer (DTC). This paper evaluates the tumour dosimetry and response following -iodine-131 treatment of metastatic thyroid cancer patients after rhTSH stimulation instead of classical hormone withdrawal-induced hypothyroidism. Nineteen consecutive (131)I treatments in 16 patients were performed after rhTSH stimulation. All patients had undergone a near-total thyroidectomy followed by an ablative dosage of (131)I. They all suffered from metastatic or recurrent disease showing tumoral (131)I uptake on previous post-treatment scintigraphy. Dosimetric calculations were performed using (131)I tumour uptake measurements from post-treatment (131)I scintigrams and tumour volume estimations from radiological images. Response was assessed by comparing pre-treatment serum thyroglobulin (Tg) level with the Tg level 3 months post treatment. In 18 out of 19 treatments, uptake of (131)I in metastatic or recurrent lesions was seen. The median tumour radiation dose was 26.3 Gy (range 1.3-368 Gy), and the median effective half-life was 2.7 days (range 0.5-6.5 days). Eleven of 19 treatments (10/16 patients) were evaluable for response after 3 months. (131)I therapy with rhTSH resulted in a biochemical partial response in 3/11 or 27% of treatments (two patients), biochemical stable disease in 2/11 or 18% of treatments and biochemical progressive disease in 6/11 or 55% of treatments. Our study showed that although tumour doses in DTC patients treated with (131)I after rhTSH were highly variable, 45% of treatments led to disease stabilisation or partial remission when using rhTSH in conjunction with (131)I therapy, without serious side-effects and with minimal impact on quality of life. RhTSH is therefore adequately satisfactory as an adjuvant tool in therapeutic settings and is especially suitable in advanced recurrent or metastatic DTC patients who may be intolerant to TSH stimulation by levothyroxine withdrawal.

Radioiodine ablation and therapy in differentiated thyroid cancer under stimulation with recombinant human thyroid-stimulating hormone

We investigated whether recombinant human TSH (rhTSH) safely and effectively induces uptake of high-dose 131-iodine (131I) to ablate thyroid remnant or treat disease, in patients with well-differentiated thyroid carcinoma. Eleven consecutive patients unable to tolerate thyroid hormone withdrawal received one im injection of 0.9 mg rhTSH on 2 consecutive days before receiving 4000 MBq (approximately 108 mCi) radioiodine orally. Eight patients received one, and 3 patients 2 courses. Our series comprised 7 women and 4 men (mean age, 78 yr, range: 56-87 yr). Ten patients had undergone total or near-total thyroidectomy up to 19 yr earlier. rhTSH-stimulated single course radioiodine with the intention to ablate thyroid remnant was performed in 3 patients, with following estimation of radioiodine uptake and TG measurements. Of another 8 patients given this treatment palliatively, 5 had radiological, clinical and/or laboratory response, including: 80% decreased pathological uptake between treatment courses; pronounced decrease in bone pain; diminished symptoms; improved physical condition and quality of life; lower serum TG concentration; and/or normalization of TG recovery test. Two patients with small lung metastases on computed tomography had no detectable radioiodine uptake or other response; they also lacked uptake after withdrawal-stimulated radioiodine treatment. Despite being elderly and frail, patients generally tolerated treatment well; rhTSH caused nausea in one patient and transiently increased pain in bone and soft tissue lesions in another. We conclude that rhTSH-stimulated high-dose radioiodine for remnant ablation or tumor treatment is safe, feasible and seemingly effective, enhancing quality of life and offering reasonable palliation in patients with advanced disease.