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Published on: January 17, 2018
Characteristics and response cutoff of octreotide suppression test in thyrotrophin (TSH)-secreting pituitary adenomas
Jie Liu1, Yamei Yang2,3, Lian Duan2,3
1Department of Neurosurgery, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China.
Context:
Somatostatin analogs are recommended for preoperative therapy in thyrotrophin secreting pituitary adenomas (TSHomas). Octreotide suppression test (OST) was designed to differentiate TSHomas with resistance to thyroid hormones, while its ability to test the sensitivity of SSA has not been fully studied.
Objective:
To test the sensitivity of SSA in TSHomas with OST.
Patients:
We collected 48 pathologically confirmed TSHoma patients with complete 72 h' data of OST into analysis.
Intervention:
Octreotide suppression test.
Main Outcome:
Sensitivity timepoint and cutoff of OST.
Results:
During the entire OST, the TSH descended maximally 89.07% (73.85%, 96.77%), while the FT3 and FT4 declined slowly [43.40% (37.80%, 54.44%) and 26.59% (19.01%, 33.13%), respectively]. The 24th hour was the timepoint wherein the stability occurs for TSH, and the 48th hour for FT3 and FT4 during OST. In the patients who received both short- and long-acting somatostatin analogs (SSA), the 24-h timepoint was the most predictive timepoint for the percentage of TSH decline (Spearman's rank correlation analysis, r = .571, p < .001), while the 72-h timepoint was optimal for predicting the magnitude of TSH decline (Spearman's rank correlation analysis, r = .438, p = .005). In the 24th timepoint, a positive correlation was also observed between TSH suppression rate and the percentage decrease and absolute value decrease of FT3 and FT4. Furthermore, in patients treated with long-acting SSA, the 72-h timepoint was optimal for predicting both the percentage (Spearman's rank correlation analysis, r = .587, p = .01) and magnitude (Spearman's rank correlation analysis, r = .474, p = .047) of TSH decline. The 24th hour was the optimal timepoint with 44.54% (50% of median value of TSH in 72-hOST) decrease of TSH being the observing cutoff. The adverse effect of OST was predominantly occurred in the gastrointestinal system and no severe event occurred during OST. Paradoxical response could occur in OST and it did not influence the effect of SSA as long as sensitivity was confirmed. A high level of hormonal control was achieved in the SSA-sensitive patients.
Conclusion:
OST can be used as an efficient tool to guide the adequate use of SSA.
Insights
The Octreotide Suppression Test (OST) effectively assesses somatostatin analog (SSA) sensitivity in thyrotropin-secreting pituitary adenomas (TSHomas). The 24-hour mark is optimal for predicting TSH decline, guiding SSA therapy.
Area of Science:
- Endocrinology
- Oncology
- Pharmacology
Background:
- Somatostatin analogs (SSAs) are crucial for preoperative therapy in thyrotropin-secreting pituitary adenomas (TSHomas).
- The Octreotide Suppression Test (OST) is used to differentiate TSHomas resistant to thyroid hormones.
- The efficacy of OST in assessing SSA sensitivity in TSHomas requires further investigation.
Purpose of the Study:
- To evaluate the sensitivity of SSA in TSHomas using the OST.
- To determine optimal timepoints and cutoffs for OST in assessing SSA sensitivity.
Main Methods:
- Analysis of 72-hour OST data from 48 pathologically confirmed TSHoma patients.
- Assessment of TSH, FT3, and FT4 levels during OST.
- Correlation analysis to identify predictive timepoints for TSH decline.
Main Results:
- TSH levels maximally decreased by 89.07% during OST, with slower declines in FT3 and FT4.
- The 24-hour timepoint was most predictive for TSH decline percentage, while 72-hour was optimal for magnitude.
- A 44.54% TSH decrease at 24 hours was identified as an optimal cutoff for SSA sensitivity.
Conclusions:
- OST is an effective tool for guiding the appropriate use of SSA in TSHoma management.
- The 24-hour OST provides valuable insights into SSA sensitivity and predicts treatment response.
- OST facilitates personalized therapeutic strategies for TSHoma patients.
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