Procedure guidelines for radioiodine therapy of differentiated thyroid cancer (version 2)

Cost-effectiveness of using recombinant human TSH prior to radioiodine ablation for thyroid cancer, compared with treating patients in a hypothyroid state: the German perspective

OBJECTIVE

This investigation evaluated the cost-effectiveness of radioiodine remnant ablation following preparation with recombinant human TSH (rhTSH), compared with the standard preparation, whereby patients are rendered hypothyroid.

DESIGN

The economic evaluation relates to patients with well differentiated thyroid cancer who have undergone thyroidectomy, but have no metastases. The evaluation takes a societal perspective, considering costs and benefits to all parties. The benefits were expressed in units of quality-adjusted life years (QALY), so differences in life expectancy were captured with consideration of quality of life.

METHODS

A lifetime Markov model with Monte Carlo simulation of 100,000 patients was used to assess cost per QALY gained. The clinical inputs were sourced from a multi-centre, randomised controlled trial comparing remnant ablation success after rhTSH-preparation with hypothyroid preparation. The model applied German unit costs, however, the structure is generalisable to other jurisdictions. The additional cost of rhTSH procurement and administration is considered relative to the clinical benefits and cost offsets. These included avoidance of hypothyroidism, increased work productivity, earlier discharge from radioprotection and a theoretical reduction in the risk of secondary malignancy. The latter two benefits relate to faster radioiodine clearance after rhTSH preparation.

RESULTS

The additional benefits of rhTSH (0.0495 QALY) are obtained with an incremental societal cost of 47 euro, equating to an incremental cost per QALYof 958 euro. Sensitivity analyses had only a modest impact upon cost-effectiveness, with all one-way sensitivity results remaining under 15,000 euro/QALY.

CONCLUSIONS

The use of rhTSH prior to radioiodine ablation represents good value-for-money with the benefits to patient and society obtained at modest net cost.

Cell death induced by 131I in a differentiated thyroid carcinoma cell line in vitro: Necrosis or apoptosis?

AIM

The apoptotic and necrotic dose-response of thyroid carcinoma cells following irradiation with I was evaluated.

METHODS

In our in-vitro model, cells of well-differentiated papillary thyroid carcinoma (B-CPAP) were incubated with increasing activity concentrations of I for 2 days. Changes in cell viability and the extents of necrosis and apoptosis were evaluated both immediately and 2 days after irradiation.

RESULTS

Viability of B-CPAP cells diminished with increasing I activity concentration. No apoptosis was detectable immediately after irradiation. Two days after irradiation significant apoptosis was found. The lowest I activity concentration at which apoptosis was detectable corresponds to about 1 MBq . ml. At higher activity concentrations a larger percentage of cells became apoptotic but the proportion decreased again at activity concentrations >10 MBq . ml. Likewise, necrosis was minimal at low activity concentrations and showed an exponential increase with rising I activity concentrations (>5-10 MBq . ml). Necrosis was already detectable immediately after irradiation and was the predominant form of cell death at high activity concentrations.

CONCLUSION

The data suggest that the nature of the cytotoxic effect of I and whether it leads to apoptotic or necrotic cell death is dose-dependent. High I doses seem to produce mainly necrotic phenomena, whereas at low I activity concentrations apoptotic phenomena prevail. The predominance of delayed apoptosis could explain why radioiodine therapy at lower doses is often linked to delayed onset and possible continuation of thyroid volume reduction over some months and even up to a year.