Cost-effectiveness analysis of 18F-FDG PET/CT in detecting suspected recurrence or metastasis in well-differentiated thyroid carcinoma patients with negative diagnostic total body scan in Thailand: a decision analysis.

OBJECTIVE: To evaluate cost-effectiveness analysis of 18F-FDG PET/CT to detect tumor recurrence or metastasis in well-differentiated thyroid cancer patients with high Tg but negative TBS in Thailand. MATERIAL AND METHOD: A retrospective literature review of 55 studies published between 1978 and 2010 was done. Decision analysis by TreeAge program showed an evaluation of the most cost-effective treatment and 18F-FDG PET/CT scan in thyroid cancer patients with high Tg but negative TBS. The incremental cost and life years gained associated with seven strategies approached were analyzed by the decision tree model. The first strategy was treatment with empirical high dose 131I therapy. The second to the seventh strategies were using imaging investigations by CT scan of neck and chest, 99mTc MIBI scan, and 18F-FDG PET/CT scan to identify recurrent, persistent, and metastatic lesions before the specific treatment via curative surgery, external radiotherapy, and high dose 131I therapy. All strategies were adopted using hospital perspective and direct medical cost was estimated based on the reference price of Siriraj Hospital. Deterministic sensitivity analysis was conducted to investigate the effect of the cost of PET/CT scan. RESULTS: The strategy using 18F-FDG PET/CT scan to detect recurrence or metastasis and possible curative surgery in operable cases and high dose 131I therapy in inoperable cases gave the highest life years gained of 27.08 with cost of 90,227.61 Baht (2,926.24 US dollars) and acceptable incremental cost effectiveness ratio (ICER) of 6,936.88 Baht (224.98 US dollars) per life year gained when compared to the least costly strategy using 99mTc MIBI scan and additional 18F-FDG PET/CT scan in negative MIBI result. Other strategies were dominated by this PET/CT strategy. Deterministic sensitivity analysis (based on the willingness to pay (WTP) 360,000 Baht (11,675.42 US dollars) showed that the cost of PET/CT scan has no impact on the net health benefit. CONCLUSION: Based on the hospital perspective, the cost-effectiveness of 18F-FDG PET/CT scan in detecting suspected recurrence or metastasis in thyroid carcinoma patients with negative diagnostic TBS but high Tg was first done using 18F-FDG PET/CT scan to identify disease, followed by curative surgery or high dose 131I therapy. Moreover cost of PET/CT scan did not influence the net health benefit. This PET/CT benefit is helpfulfor considering the proper PET/CT use for thyroid cancer in Thailand.

The correlation of post-operative radioiodine uptake and Tc-99m pertechnetate thyroid scintigraphy and the result of thyroid remnant ablation.

OBJECTIVE: Determine the relationship between postoperative thyroid remnant using 24 h radioiodine uptake and Tc-99m pertechnetate scintigraphy, and the success of high dose radioiodine ablation. MATERIAL AND METHOD: Retrospectively enrolled 250 patients with DTC who underwent thyroidectomy and radioiodine ablation. Postoperative Tc-99m pertechnetate and 24 h 1-131 uptake were reviewed to evaluate thyroid remnant and the directly compared with ablation outcome. The successful ablation was defined using negative WBS and stimulated Tg < 10 ng/ml in the absence of TgAb at six to 12 months after treatment. The relationship between success of ablation and other variables were evaluated RESULTS: One hundred twenty four patients (49.6%) were successfully ablated after single high dose radioiodine ablation. The authors found no association with age, sex, extent of surgery, tumor histology, tumor size, mutifocal, extrathyroidal invasion, 1-131 administered dose, interval from surgery to radioiodine ablation, Tc-99m pertechnetate scan, or 24 h 1-131 uptake, and successful ablation. The initial Tg level was the only variable found to be associated with success (p < 0.001). CONCLUSION: Neither Tc-99m pertechnetate thyroid scintigraphy nor 24 h 1-131 uptake percentage in the evaluation of postsurgical thyroid remnant can predict radioiodine ablation outcome in patients with DTC. Serum Tg level at the time of ablation could be a reasonable predictor of the success of ablation.

A prospective randomized study of the efficacy and cost-effectiveness of high and low dose regimens of I-131 treatment in hyperthyroidism.

OBJECTIVE: To compare the efficacy and cost-effectiveness of high and low dose regimens of I-131 treatment in patients with hyperthyroidism. MATERIAL AND METHOD: One hundred fifty patients with proven hyperthyroidism were randomly allocated into the high (74 patients) and low (76 patients) dose regimen of I-131 treatment. Four patients of the high dose group and one patient of the low dose group were excluded because of lost follow-up. A gland-specific dosage was calculated on the estimated weight of thyroid gland and 24-hour I-131 uptake. The high and low I-131 dose regimens were 150 microCi/gm and 100 microCi/gm, respectively. The first mean radioiodine activity administered to the high and low dose group was 10.2 and 8 mCi, respectively. Repeated treatment was given to 25 patients of the high dose group and 40 patients of the low dose group. Clinical outcome and calculated costs for outpatient attendances, and laboratory tests together with initial and subsequent treatments were evaluated for one year after I-131 treatment. Elimination of hyperthyroidism that resulted in either euthyroidism or hypothyroidism was classified as therapeutic success. The cost effectiveness was also compared. RESULTS: At 6 months after treatment, 45 (64.3%) patients receiving high dose and 59 (78.7%) patients receiving low dose were hyperthyroidism. Clinical outcome at one year showed persistence of hyperthyroidism in 21 (30%) patients of the high dose regimen and 36 (48%) patients of the low dose regimen. At one year post treatment, it was demonstrated that the high dose regimen could eliminate hyperthyroidism in a significantly shorter time than the low dose regimen, i.e., 259.6 days and 305.5 days, respectively, p = 0.008). For the persistent hyperthyroid patients, the average total cost of treatment in the low dose group was significantly higher than that of the high dose group, i.e., 13,422.78 baht and 10,942.79 baht, respectively; p = 0.050). CONCLUSION: A high dose regimen of radioactive iodine treatment is more effective than the low dose regimen. The successful outcome of a high dose regimen occurred significantly earlier than that of the low dose regimen. For the persistent hyperthyroid patients, the average total cost in the low dose group was significantly higher than that of the high dose group.