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Objective:To explore the value of octreotide suppression test(OST) in predicting the efficacy of somatostatin receptor ligands(SRLs) in the treatment of active acromegaly.Methods:The clinical data of 76 patients with active acromegaly from 2011 to 2020 was retrospectively analyzed. OST was carried out as follows: After an overnight fasting and baseline sampling of growth hormone(GH), 100 μg octreotide was subcutaneously injected, and sampling for GH was obtained every 2 hours for 8 hours. All patients were treated with SRLs for at least 3 months. A good GH response is defined as a post-treatment random GH<1 μg/L or >80% fall compared with the baseline GH. A good insulin-like growth factor Ⅰ(IGF-Ⅰ) response is defined as IGF-Ⅰ<1.3 upper limit of normal(ULN) or >50% reduction compared with the baseline. If both GH and IGF-Ⅰ fulfill the criteria of a good response, it is defined as a good GH and IGF-Ⅰ response.Results:The baseline level of GH during OST was 15.00(6.38, 34.20) μg/L, the median time to reach the nadir GH was(3.65±1.65) hours, and the nadir GH level was 1.47(0.50, 4.19) μg/L. The median GH suppression rate was 89.12%(72.71%, 95.09%). When the cutoff value of GH suppression rate in predicting a good GH response was 89.32%, the area under the curve(AUC) was 0.74, with a sensitivity of 81.80% and specificity of 66.00%. When the cutoff value of GH suppression rate in predicting a good IGF-Ⅰ response was 93.14%, the AUC was 0.64, with a sensitivity of 50.00% and specificity of 75.60%. When the GH suppression rate was 90.71%, the AUC was 0.78, with the sensitivity of 83.30% and specificity of 70.00% in predicting a good GH and IGF-Ⅰ response. Compared with GH/IGF-Ⅰ non-responders, GH/IGF-Ⅰ responders displayed lower nadir GH during OST, higher GH suppression rate and IGF-Ⅰ reduction rate, and lower ratio of IGF-1 to ULN( P<0.05). Conclusion:GH suppression rate during the OST is a valuable predictor to evaluate the efficacy of SRLs in patients with acromegaly, with the highest sensitivity and specificity when the cutoff value is 90.71%.
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Objective:To outline clinical features in syndrome of resistance to thyroid hormone(RTH) and thyrotropin-secreting pituitary adenoma(TSH adenoma) based on a case series, and to assess the value of octreotide suppression test and high-dose dexamethasone suppression test(HDDST) in differentiating the two diseases.Methods:A total of 22 cases with RTH and TSH adenoma clinically diagnosed in Xiangya Hospital of Central South University from October 2010 to December 2021 were retrieved. The clinical characteristics of the two diseases and results to different tests were analyzed and summarized.Results:(1) The tumors in TSH adenoma patients were larger than those with RTH complicated with pituitary mass, which presented chiasmatic compression on images( P<0.05). (2) In octreotide suppression test, thyrotropin(TSH) inhibition rate in RTH patients was lower than that in TSH adenoma patients( P<0.05). In HDDST, TSH inhibition rate was higher in patients with RTH than in patients with TSH adenoma( P<0.05). (3) The TSH inhibition rate was calculated by receiver operating characteristic(ROC) curve. The sensitivity and specificity of octreotide suppression test were 91.9% and 55.6%, respectively, and the threshold value of TSH inhibition rate was 64.24%. The sensitivity and specificity of HDDST were 54.4% and 89.0%, respectively, and the threshold value of TSH inhibition rate was 65.73%.The combined sensitivity and specificity of the two tests were 77.8% and 90.9%, indicating better diagnostic value( P<0.05). Conclusions:The combination of octreotide suppression test and HDDST is of clinical value in differentiating RTH from TSH adenoma. TSH adenoma is more aggressive than that of pituitary adenoma with RTH.
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Aims:To determine whether the use of an octreotide suppression test will reliably distinguish pituitary from ectopic ACTH overproduction. Somatostatin receptors are expressed in NETs, but are downgraded in the pituitary as the result of hypercortisolaemia. Octreotide should therefore lower ACTH and cortisol levels in patients with NETs but not in patients with Cushing’s disease and pituitary tumors. Methodology:A cross sectional study was performed in 13 patents with ACTH dependent Cushing’s (8 women, 5 men) with ages ranging between 21 to 40 years were studied. Serum cortisol concentrations were measured at 0800 hrs before and during the administration of. Octreotide at a dosage of 100 mcg subcutaneously every 8 hours for 72 hours.Results:The serum cortisol concentrations returned to normal in 4 patients who were later documented to have ectopic disease, two with typical bronchial carcinoids and two with pancreatic NETs and metastatic disease. The other 9 patients had no suppression in serum cortisol concentrations and were documented later to have pituitary tumours.Conclusion:These results indicate that a short trial of octreotide will identify patients with ectopic disease as evidenced by a fall inserum cortisol levels whereas in those with Cushing’s disease and pituitary tumours serum cortisol levels remains unchanged. Recommendation: We recommend all patients with ACTH dependent Cushing’s syndrome have an octreotidesuppression test, even if the MRI shows an adenoma, so as to exclude the possibility of a pituitary incidentaloma in a patient with ectopic disease, or false localization from IPSS to the pituitary gland due to ectopic CRH secretion