Somatostatin Analogues In Patients Research Articles

Volumetric parameters of 68[Ga]Ga-DOTA-TATE PET/CT in the prediction of response to treatment with long-acting somatostatin analogues in patients with well-differentiated NETs

Volumetric parameters of 68[Ga]Ga-DOTA-TATE PET/CT in the prediction of response to treatment with long-acting somatostatin analogues in patients with well-differentiated NETs

THU511 Somatostatin Analogs Or Active Surveillance In Sporadic And MEN1 Associated Non-functioning Pancreatic Neuroendocrine Tumors

Abstract Disclosure: S. Raia: None. S. Chiloiro: None. M. Maratta: None. B. Maiorano: None. E. Rossi: None. M. Brizi: None. V. Rufini: None. L. De Marinis: None. G. Rindi: None. G. Schinzari: None. A. Pontecorvi: None. G. Tortora: None. A. Bianchi: None. Introduction: Non-functioning (NF), sporadic and MEN1 associated, G1-G2 pancreatic neuroendocrine tumors (PanNETs) usually display an indolent course. Surgery is the first-choice treatment for localized tumors >2 cm. Unresectable or metastatic PanNETs expressing somatostatin receptors (SSTRs) are treated with somatostatin analogs (SSAs). The standard treatment for patients with PanNETs ≤2cm is active surveillance (AS). Yet no evidence of the value of SSA treatment exist in such patient population. Aim(s): To assess the clinical value of SSAs in patients with PanNETs ≤2cm. Material and methods: Data from patients (pts) NF, G1-G2 PanNETs≤2cm were retrospectively collected. Median progression-free survival (mPFS) and response rate (RR) were analyzed in SSA group and AS group. Results: From June 2007 to June 2022, data from 46 pts were considered: 29 pts, who declined an AS program but had not indication for surgery, entered in the SSA group (21 sporadic and 8 MEN1 associatd PanNET) and 17 in the AS group. At a median follow-up of 64.8 months for sporadic and of 63.9 for MEN1 associated PanNET, no disease progression (PD) was reported in the SSA group, without differences between sporadic and MEN1 associated PanNET. While the PD rate was 23.5 % in the AS group, with a mPFS of 36.2 months. Conclusion: SSAs therapy showed significant antiproliferative activity in patients with both sporadic and MEN1 associated NF, G1-G2 PanNETs ≤2cm. SSAs treatment delay tumor progression and distant spread in small lesions that sometimes may reveal an unpredictable aggressiveness. Presentation: Thursday, June 15, 2023

The Role of Somatostatin Analogues in the Control of Diarrhea and Flushing as Markers of Carcinoid Syndrome: A Systematic Review and Meta-Analysis

Somatostatin analogues (SSAs) are the cornerstone of treatment for carcinoid syndrome (CS)-related symptoms. The aim of this systematic review and meta-analysis is to evaluate the percentage of patients achieving partial (PR) or complete response (CR) with the use of long-acting SSAs in patients with CS. A systematic electronic literature search was conducted in PubMed, Cochrane, and Scopus to identify eligible studies. Any clinical trials reporting data on the efficacy of SSAs to alleviate symptoms in adult patients were considered as potentially eligible. A total of 17 studies reported extractable outcomes (PR/CR) for quantitative synthesis. The pooled percentage of patients with PR/CR for diarrhea was estimated to be 0.67 (95% confidence interval (CI): 0.52-0.79, I2 = 83%). Subgroup analyses of specific drugs provided no evidence of a differential response. With regards to flushing, the pooled percentage of patients with PR/CR was estimated to be 0.68 (95% CI: 0.52-0.81, I2 = 86%). Similarly, no evidence of a significant differential response in flushing control was documented. We estimate there is a 67-68% overall reduction in symptoms of CS associated with SSA treatment. However, significant heterogeneity was detected, possibly revealing differences in the disease course, in management and in outcome definition.

Real-world outcomes in patients with gastroenteropancreatic neuroendocrine tumors receiving somatostatin analogue: Data from a public hospital in Brazil.

650 Background: Neuroendocrine tumors are rare malignant neoplasms derived from endocrine cells and known for their heterogeneous behavior and histopathological characteristics; however, largely associated with a favorable clinical outcome. Somatostatin analogues (SSA) were initially used to control the symptoms of secretory neuroendocrine tumors, and later, they were considered effective as a first-line systemic treatment in unresectable or metastatic neuroendocrine tumors of the gastroenteropancreatic tract (NET-GEP). Randomized clinical trials are performed in controlled environments, with strict inclusion and exclusion criteria, and therefore, real-world studies can add to efficacy and safety data in the general population. Methods: To evaluate, in the real world scenario of a tertiary hospital of the public health system, the efficacy and toxicities of first-line treatment with somatostatin analogue in patients diagnosed with unresectable or metastatic NET-GEP, to find real-world progression free survival (rwPFS) and real-world overall survival (rwOS), in addition to the toxicity profile in our population and possible subgroups that benefit from first-line treatment, through the analysis of variables. Results: 29 patients met the study inclusion criteria, which were diagnosed in the period from 2009 to 2017. The median wrSLP and wrSG were 4.4 (95% CI 3.2 – 5.6) and 8.2 years (CI 95% 6.2 – 10.2), respectively. In an adjusted analysis of rwSLP, the HR for patients with hindgut tumors compared to midgut tumors was 4.41 with p 0.05, indicating that these patients had a 4x increased risk for disease progression (p 0 .05). In the adjusted analysis of wrSG, a trend towards a more favorable evolution was observed in the group of patients with well-differentiated tumors, with p 0.05. Assessment of toxicities revealed grade 2 and grade 3 adverse events in 34.48% of patients. Abdominal pain was the most incident toxicity, occurring in 17.24%, followed by headache (13.79%) and diarrhea (10.34%). Conclusions: Treatment with SSA was effective in our sample, with rwPFS and rwOS data above those found in randomized clinical trials. The toxicities were easily manageable and caused no documented harm to patients.

Prescription patterns of somatostatin analogs in patients with acromegaly and neuroendocrine tumors

PurposeAcromegaly and neuroendocrine tumors are rare diseases that, under certain conditions, can be treated with somatostatin analogs. The aim was to determine the prescription patterns of somatostatin analogs in a group of patients with acromegaly and neuroendocrine tumors affiliated with the Colombian Health System.MethodsA retrospective study. A cohort of patients from a drug dispensing database that collected all prescriptions of long-acting somatostatin analogs (octreotide, lanreotide, pasireotide). Sociodemographic variables, clinical variables (diagnosis and comorbidities) and pharmacological therapy variables (dose, changes, persistence of use, comedications) were considered.ResultsA total of 213 patients were identified, including 139 (65.3%) with acromegaly and 74 (34.7%) with neuroendocrine tumors. There was a predominance of women (58.7%) and a mean age of 59.7 ± 14.5 years. The most commonly used medications were lanreotide autogel (n = 107; 50.2%), octreotide LAR (n = 102; 47.9%) and pasireotide LAR (n = 4; 1.9%). During follow-up, 11.3% of patients experienced modifications of therapy, with a mean duration from the beginning of treatment to the change in medication of 25 ± 15.9 months. A total of 48.9% of the patients with acromegaly and 87.1% of individuals with neuroendocrine tumors received maximum approved doses of the drug.ConclusionPatients with acromegaly and neuroendocrine tumors in Colombia are mainly women and are most frequently treated with lanreotide autogel for acromegaly and with octreotide LAR for neuroendocrine tumors. In addition, a high proportion are managed with maximum doses of long-acting somatostatin analogs.

Tumor-induced Osteomalacia: A Systematic Review and Individual Patient's Data Analysis.

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome, usually caused by small, benign, and slow-growing phosphaturic mesenchymal tumors. Clinically, TIO is characterized by renal phosphate leak, causing hypophosphatemia and osteomalacia. This review was performed to assess the clinical characteristics of TIO patients described worldwide so far. On June 26, 2021, a systematic search was performed in Medline, Google Scholar, Google book, and Cochrane Library using the terms: "tumor induced osteomalacia," "oncogenic osteomalacia," "hypophosphatemia." There were no language restrictions. This review was performed according to Preferred Reporting Items for Systematic reviews and Meta-Analyses criteria. Overall, 1725 TIO cases were collected. TIO was more frequent in adult men, who showed a higher incidence of fractures compared with TIO women. The TIO-causing neoplasms were identified in 1493 patients. The somatostatin receptor-based imaging modalities have the highest sensitivity for the identification of TIO-causing neoplasms. TIO-causing neoplasms were equally located in bone and soft tissues; the latter showed a higher prevalence of fractures and deformities. The surgery is the preferred TIO definitive treatment (successful in > 90% of patients). Promising nonsurgical therapies are treatments with burosumab in TIO patients with elevated fibroblast growth factor-23 levels, and with radiolabeled somatostatin analogs in patients with TIO-causing neoplasm identified by somatostatin receptor-based imaging techniques. TIO occurs preferentially in adult men. The TIO clinical expressiveness is more severe in men as well as in patients with TIO-causing neoplasms located in soft tissues. Treatments with burosumab and with radiolabeled somatostatin analogs are the most promising nonsurgical therapies.

Long action somatostatin analogues in patients with TSH-secreted pituitary adenomas: treatment experience

Thyrotoxicosis, which characteristics are increased excitability, emotional lability, tachycardia episodes, increasing of free fractions of tetraiodothyronine (T4) and triiodothyronine (T3) is one of the most common endocrinological syndromes. However, during the interpretation of thyroid status it is very important to take into account the possibility that a patient has TSH-secreting pituitary adenoma. Timely diagnosis of TSH-secreting adenomas plays prominent role in guiding the treatment course since it is associated with an improvement of long-term prognosis and an increase of the patient’s total life expectancy. Needed to underline that in some patients with TSH-secreting adenomas manifestations of the other pituitary hormones hypersecretion (first of all — somatotropin and prolactin) come to the fore, that lead to the development of acromegaly and hyperprolactinemia accordingly. Our work basing on two clinical cases presents main principles of diagnosis and specific clinical manifestations of TSH-secreting pituitary adenomas and demonstrates efficacy of somatostatin analogues in the treatment of this pathology.

Somatostatin analogs in patients with Zollinger Ellison syndrome (ZES): an observational study.

Zollinger Ellison syndrome (ZES) is a rare syndrome caused by gastrin hypersecretion from a gastrinoma. Gastrinoma treatment has two goals: the control of acid hypersecretion and the control of tumor growth. While therapy for the syndrome is univocally based on proton pump inhibitors, the one for disease control is still debated. We here aimed at evaluating the role of somatostatin analogs (SSAs) in the control of tumor progression in a series of ZES patients. A retrospective analysis of a prospectively collected database of ZES patients, followed and managed from 1990 to 2019, was performed. The patients' clinical, pathological, treatment, and follow-up data were analyzed. Data regarding SSAs therapy start, dosage, duration, and side effects were collected. 33 patients with ZES were diagnosed. Fourteen patients (42%) had a grade 1 (G1) neuroendocrine neoplasm (NEN), five had G2 (15%), none had G3. Fifteen patients (45%) had metastatic disease. Overall, 12 (36%) underwent SSAs therapy. The median treatment duration was 36 months. Eight patients (67%) had a sustained response to SSAs, four (33%) showed an early progression, with a significant difference in terms of PFS between the patients with early and late progression (84 vs 2 months, p = 0.004). No differences in terms of OS and PFS were observed between the treated and non-treated patients, despite the proportion of metastatic patients was greater in the SSAs-treated group (75% vs 29% in the non-treated group, p = 0.01). Present data support the use of SSAs in ZES, considering that gastrinoma is mainly a well-differentiated low-grade tumor (G1 or G2), with a high expression of somatostatin receptors.

Effectiveness and predictors of response to somatostatin analogues in patients with gastrointestinal angiodysplasias: a systematic review and individual patient data meta-analysis

Gastrointestinal angiodysplasias are vascular malformations that often cause red blood cell transfusion-dependent anaemia. Several studies suggest that somatostatin analogues might decrease rebleeding rates, but the true effect size is unknown. We therefore aimed to investigate the efficacy of somatostatin analogues on red blood cell transfusion requirements of patients with gastrointestinal angiodysplasias and to identify subgroups that might benefit the most from somatostatin analogue therapy. We did a systematic review and individual patient data meta-analysis. We searched MEDLINE, Embase, and Cochrane on Jan 15, 2016, with an updated search on April 25, 2021. All published randomised controlled trials and cohort studies that reported on somatostatin analogue therapy in patients with gastrointestinal angiodysplasias were eligible for screening. We excluded studies without original patient data, single case reports, small case series (ie, <10 participants), studies in which patients had a specific aetiology of gastrointestinal angiodysplasias, and studies in which somatostatin analogue therapy was initiated simultaneously with other treatment modalities. Authors of eligible studies were invited to share individual patient data. Aggregated data was used if individual patient data were not provided. The primary outcome was the mean reduction in the number of red blood cell transfusions during somatostatin analogue therapy, compared with baseline, expressed as the incidence rate ratio (IRR) and absolute mean decrease. We defined patients as either good responders (≥50% reduction in the number of red blood cell transfusions) or poor responders (<50% reduction). A mixed-effects negative binomial regression was used to account for clustering of patients and skewness in data. This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO), number CRD42020213985. We identified 11 eligible studies (one randomised controlled trial and ten cohort studies) of moderate-to-high quality and obtained individual patient data from the authors of nine (82%) studies. The remaining two (18%) studies provided sufficient information in the published manuscript to extract individual patient data. In total, we analysed data from 212 patients. Somatostatin analogues reduced the number of red blood cell transfusions with an IRR of 0·18 (95% CI 0·14-0·24; p<0·0001) during a median treatment duration of 12 months (IQR 6·0-12·0) and follow-up period of 12 months (12·0-12·0), correlating with a mean absolute decrease in the number of red blood cell transfusions from 12·8 (95% CI 10·4-15·8) during baseline to 2·3 (1·9-2·9) during follow-up-ie, a reduction of 10·5 red blood cell transfusions (p<0·0001). 177 (83%) of 212 patients had a good response to somatostatin analogue therapy (defined as at least a 50% reduction in the number of red blood cell transfusions). Heterogeneity across studies was moderate (I2=53%; p=0·02). Location of gastrointestinal angiodysplasias in the stomach compared with angiodysplasias in the small bowel and colon (IRR interaction 1·92 [95% CI 1·13-3·26]; p=0·02) was associated with worse treatment response. Octreotide was associated with a better treatment response than lanreotide therapy (IRR interaction 2·13 [95% CI 1·12-4·04]; p=0·02). The certainty of evidence was high for the randomised controlled trial and low for the ten cohort studies. Adverse events occurred in 38 (18%) of 212 patients receiving somatostatin analogue therapy, with ten (5%) discontinuing this therapy because of adverse events. The most common adverse events were loose stools (seven [3%] of 212), cholelithiasis (five [2%]), flatulence (four [2%]), and administration site reactions (erythema, five [2%]). Somatostatin analogue therapy is safe and effective in most patients with red blood cell transfusion-dependent bleeding due to gastrointestinal angiodysplasias. Somatostatin analogue therapy is more effective in patients with angiodysplasias located in the small bowel and colon, and octreotide therapy seems to be more effective than lanreotide therapy. The Netherlands Organisation for Health Research and Development and the Radboud University Medical Center.

A Rapid and Safe Infusion Protocol for 177Lu Peptide Receptor Radionuclide Therapy.

Peptide receptor radionuclide therapy (PRRT) with 177Lu-labeled somatostatin analogs in patients with somatostatin receptor-expressing tumors is often performed using administration protocols prescribing a 30-min infusion time. The most often used method of infusion is the gravity method, by which the complete dose is effectively administered exponentially. However, there is no evidence to explicitly support an infusion time of 30 min. This study aims to investigate the safety of an infusion time of less than 5 min. Methods: A cohort study was performed, examining the biochemical and clinical toxicity after PRRT when using a fast-infusion protocol with a maximum infusion time of 5 min. Data on patient characteristics, laboratory tests, follow-up visits, and pre- and posttreatment imaging using 68Ga-DOTATOC PET/CT from patients treated with PRRT at the University Medical Center Utrecht (UMC Utrecht) were collected. All patients receiving PRRT using the fast-infusion protocol were included. If no laboratory or clinical follow-up was available, patients were excluded. In addition, a laboratory experiment was performed, simulating the standard-infusion protocol using the gravity method. Results: Thirty-one patients, treated using the fast-infusion protocol, were included. Clinical toxicity mainly consisted of grade 1/2 fatigue (87.1%) and grade 1 nausea or vomiting (67.7%) during follow-up. No acute or long-term clinical toxicity possibly related to the fast-infusion protocol was reported. Grade 3/4 hematologic toxicity occurred after PRRT in 1 patient (3.2%). No grade 3/4 renal toxicity occurred. The laboratory experiment showed that when using the gravity method for infusion, half of the activity is infused after 3.5 min, and 95% is infused within 15 min. Conclusion: A faster infusion of PRRT using an infusion time of less than 5 min is safe and feasible in clinical practice.

PCN9 Bayesian Network Meta-Analyses of the Efficacy of LONG-Acting Release Somatostatin Analogs in Patients with Advanced Neuroendocrine Tumors: Application of Different Parametric and Fractional Polynomial Methods

PCN9 Bayesian Network Meta-Analyses of the Efficacy of LONG-Acting Release Somatostatin Analogs in Patients with Advanced Neuroendocrine Tumors: Application of Different Parametric and Fractional Polynomial Methods

High somatostatin receptor expression and efficacy of somatostatin analogues in patients with metastatic Merkel cell carcinoma.

Merkel cell carcinoma (MCC) is an aggressive, high-grade, cutaneous neuroendocrine tumour (NET). Agents blocking programmed death 1/programmed death ligand 1 have efficacy in metastatic MCC (mMCC), but half of patients do not derive durable benefit. Somatostatin analogues (SSAs) are commonly used to treat low- and moderate-grade NETs that express somatostatin receptors (SSTRs). To assess SSTR expression and the efficacy of SSAs in mMCC, a high-grade NET. Methods In this retrospective study of 40 patients with mMCC, SSTR expression was assessed radiologically by somatostatin receptor scintigraphy (SRS; n = 39) and/or immunohistochemically when feasible (n = 9). Nineteen patients (18 had SRS uptake in MCC tumours) were treated with SSA. Disease control was defined as progression-free survival (PFS) of ≥ 120 days after initiation of SSA. Thirty-three of 39 patients (85%) had some degree (low 52%, moderate 23%, high 10%) of SRS uptake. Of 19 patients treated with SSA, seven had a response-evaluable target lesion; three of these seven patients (43%) experienced disease control, with a median PFS of 237 days (range 152-358). Twelve of 19 patients did not have a response-evaluable lesion due to antecedent radiation; five of these 12 (42%) experienced disease control (median PFS of 429 days, range 143-1757). The degree of SSTR expression (determined by SRS and/or immunohistochemistry) did not correlate significantly with the efficacy endpoints. In contrast to other high-grade NETs, mMCC tumours appear frequently to express SSTRs. SSAs can lead to clinically meaningful disease control with minimal side-effects. Targeting of SSTRs using SSA or other novel approaches should be explored further for mMCC.

MON-288 TSH Deficiency in Patients on Somatostatin Analog for TSH-PitNET

Background: Somatostatin analogs (SSA) are efficiently used to control central hyperthyroidism in patients with thyrotropin-secreting pituitary neuroendocrine tumor (TSH-PitNET). The aim of this study was to describe the frequency of thyrotropin (TSH) deficiency under SSA in patients with TSH-PitNET. Methods: We retrospectively recruited patients presenting a central hyperthyroidism due to TSH-PitNET. Inclusion criteria were patients treated in first, second or third line by short or long-acting SSA, with central hyperthyroidism before SSA. Patients treated by radiotherapy or dopamine agonist were excluded. TSH deficiency was defined by either a low FT4 or low FT4 and FT3, associated with non-elevated TSH concentrations during SSA therapy. We analyzed the frequency of TSH deficiency and the characteristics of patients with or without TSH deficiency. Results: 46 patients were included in the study. SSA were used as the first-line therapy in 21 of 46 patients (46%). Central hyperthyroidism was controlled in 36 of 46 patients (78%). TSH deficiency appeared in 7 of 46 patients (15%), after a median time of 4 weeks (4–7) after the starting of SSA, and for a median duration of 3 months (2.5–3). The TSH deficiency occurred after 1 to 3 injections of long-acting SSA. There were no differences in terms of clinical and hormonal features and size of adenomas between patients with or without TSH deficiency. Conclusions: In patients with central hyperthyroidism due to TSH-PitNET, SSA can induce TSH deficiency. Thyrotropic function should be assessed before each injection of SSA in order to adapt the frequency of injection when control of thyrotoxicosis rather than tumor reduction is purpose of the treatment.

Preoperative Somatostatin Analogues in Patients with Newly-diagnosed Acromegaly: A Systematic Review and Meta-analysis of Comparative Studies

Biochemical remission after transsphenoidal surgery is still unsatisfied in acromegaly patients with macroadenomas, especially with invasive macroadenomas. Concerning the impact of preoperative somatostatin analogues (SSAs) on surgical outcomes, previous studies with limited cases reported conflicting results. To assess current evidence of preoperative medical treatment, we performed a systematic review and meta-analysis of comparative studies. A literature search was conducted in Pubmed, Embase, and the Cochrane Library. Five randomized controlled trials (RCT) and seven non-RCT comparative studies were included. These studies mainly focused on pituitary macroadenomas though a small number of microadenoma cases were included. For safety, preoperative SSAs were not associated with elevated risks of postoperative complications. With respect to efficacy, the short-term cure rate was improved by preoperative SSAs, but the long-term cure rate showed no significant improvement. For invasive macroadenomas, the short-term cure rate was also improved, but the long-term results were not evaluable in clinical practice because adjuvant therapy was generally required. In conclusion, preoperative SSAs are safe in patients with acromegaly, and the favorable impact on surgical results is restricted to the short-term cure rate in macroadenomas and invasive macroadenomas. Further well-designed RCTs to examine long-term results are awaited to update the finding of this meta-analysis.

Nonconventional Doses of Somatostatin Analogs in Patients With Progressing Well-Differentiated Neuroendocrine Tumor.

To evaluate the antiproliferative activity and safety of nonconventional high doses of somatostatin analogs (HD-SSA) in patients with well-differentiated gastroenteropancreatic (GEP) neuroendocrine tumors (NET) with radiological disease progression according to Response Evaluation Criteria in Solid Tumors (RECIST) criteria on a previous treatment. A retrospective analysis of prospectively maintained databases from 13 Italian NET-dedicated centers was performed. Main inclusion criteria were: well-differentiated G1 or G2 GEP-NET, progressive disease on a previous treatment, and subsequent treatment with HD-SSA (either by increased administered dose [dose intensity] or shortened interval between administrations [dose density]). Main endpoints were progression-free survival (PFS) and safety. Of 198 patients, 140 matched inclusion criteria and were included in the analysis. Overall, median PFS was 31 months. Use of HD-SSA as second-line treatment was associated with reduced risk for progression or death compared with third- or further-line treatment (HR: 2.12; P = 0.004). There was no difference in PFS between HD-SSA by increased dose density (N = 133; 95%) or intensity (N = 7; 5%). Partial response according to RECIST criteria was observed in 12 patients (8.6%), and stable disease was achieved in 106 (75.7%) patients. Adverse events occurred in 21 patients (15.0%), 2 of whom had grade 3 biliary stone disease. No patients discontinued HD-SSA treatment due to adverse events. HD-SSA is an active and safe treatment option in patients with progressive well-differentiated GEP-NET. The high rate of objective responses observed deserves prospective validation in ad hoc clinical trials.

Added Value of Dynamic Contrast-Enhanced Magnetic Resonance Imaging in Predicting Response to Somatostatin Analogs in Acromegaly Patients.

To investigate the added value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) sequences in predicting somatostatin analog (SSA) responses in patients with acromegaly. This study included 55 active acromegaly patients with macroadenoma. Mean and maximum signal intensities were measured using region of interests in T2-weighted (T2W) and DCE-MRI sequences. Semi-quantitative values indicating relative signal intensity ratios and contrast-enhanced kinetics were obtained. Bivariate and multivariate analyses were used to determine whether the pathological granulation pattern of adenomas (dense versus others) was associated with patients' demographic variables and semi-quantitative MRI parameters. Three parameters formed the logistic model, x2(3)=23.278, p < 0.0001: age (odds ratio [OR]=1.08), hypointensity of adenomas in T2W images (OR=15.45), and high maximum enhancement ratio in the second interval (ER2max) values (OR=2195.74). The overall accuracy of this model was 85.45% with an area under the curve of 0.880. Sensitivity, specificity, positive predictive, and negative predictive values of the model were 68.75%, 92.31%, 78.58%, and 87.8%, respectively. In patients with newly diagnosed acromegaly, the model created based on the relative T2W signal intensity, patient's age, and ER2 < submax parameter from DCE-MRI sequences might be used to more accurately predict SSA responses.

GSTP1 gene methylation and AHR rs2066853 variant predict resistance to first generation somatostatin analogs in patients with acromegaly

Biomarkers of clinical and therapeutic outcome in acromegaly are needed. Polymorphisms or epigenetic changes of detoxification genes, such as those coding for the aryl hydrocarbon receptor (AHR) and the glutathione-S-transferase-P1 (GSTP1), could have a role in GH secreting pituitary tumors' pathophysiology and clinical expression. In this study, we assessed the contribution of GSTP1 gene promoter methylation status, per se or in combination with the occurrence of the AHR gene rs2066853 variant, on clinical features and response to somatostatin analogs (SSA) treatment in acromegaly patients. This is an observational, retrospective study, carried out in the Endocrine Unit of an Italian University Hospital. We enrolled 77 wild-type AIP gene acromegaly patients, who have been screened for germline AHR rs2066853 variant and GSTP1 gene promoter methylation. Clinical and biochemical parameters were compared after patients' stratification according to GSTP1 methylation status and the presence of AHR rs2066853. We also evaluated the response to SSA treatment in 71 cases. 17 patients carried the AHR rs2066853 variant and 26 had methylated GSTP1 (GSTP1-methyl) gene promoter. GSTP1-methyl patients showed a higher prevalence of diabetes mellitus (p = 0.01), colonic polyps (p = 0.05), and were more resistant to SSA (p = 0.02) as compared to GSTP1 unmethylated patients (GSTP1-unmethyl). Patients GSTP1-unmethyl and AHR wild-type were the most sensitive to SSA treatment, while those with both GSTP1-methyl and AHR rs2066853 variant were all resistant to SSA (p = 0.01). In acromegaly, GSTP1 gene methylation associates with resistance to SSA treatment, especially in patients carrying also the AHR rs2066853 variant, and with increased prevalence of colonic polyps and diabetes mellitus.

Magnetic resonance spectroscopy may serve as a presurgical predictor of somatostatin analog therapy response in patients with growth hormone-secreting pituitary macroadenomas.

Somatostatin analogs (SSAs) are considered one of the most effective medical treatments for patients with growth hormone-secreting pituitary adenomas (GH-PAs). The postoperative electron microscopy (EM) pathological subtype and SSTR2 expression in the tumor are the most established predictors of patient response to SSA therapy. The aim of this study was to evaluate how will magnetic resonance spectroscopy (MRS) measurements before surgery predict the EM pathological subtypes and SSTR2 expression of tumors, and thereby serve as an indicator for the therapeutic sensitivity to SSAs of patients with GH-PAs. Eighteen patients with GH pituitary macroadenomas who underwent transsphenoidal surgery were included in this retrospective study. The preoperative MRS data and T2 signal intensity were obtained from patients by 1.5 T MR spectroscopy of the sellar mass. The EM pathological subtypes of tumors were determined after surgery through examination of cell granulations. The expressions of somatostatin receptor 2 (SSTR2), SSTR5, P21, P27, and Ki-67 were evaluated by immunohistochemistry. The MRS parameters that were found to significantly predict the EM pathological subtypes of tumors, as calculated by the receiver operating characteristic curve, were the choline (Ch) value at 3140.5 MR units (sensitivity 69.2%, specificity 100%) and the choline/creatine (Ch/Cr) ratio at 1.27 (sensitivity 92.3%, specificity 100%). Further, the Ch/Cr ratio, but not other MRS data, was shown to negatively correlate with the expression of SSTR2 (P = 0.02). The Ch/Cr ratio was also found to positively correlate with the Ki-67 value (P < 0.05) and T2 signal (P < 0.05), but not with other factors that were examined in this study. Moreover, the Ch/Cr ratio could predict the EM pathological subtypes of tumors with an accuracy of 83.3% (5/6) for patients with an isointense T2 signal. The Ch/Cr ratio by MRS could effectively predict the tumor subtype and was significantly correlated with the expression of SSTR2, which was consistent with other predictors. It was also able to distinguish the patients with isointense T2 signals. Our results provide a potentially new and non-invasive method to predict the response to SSAs in patients with GH pituitary macroadenomas.

Comparison of Cabergoline Versus Raloxifene Add-On Therapy to Long-Acting Somatostatin Analogue in Patients With Inadequately Controlled Acromegaly: A Randomized Open Label Clinical Trial

The present study aimed to evaluate the efficacy of add-on therapy of cabergoline versus raloxifene to long-acting somatostatin analogues (SAs) in patients with inadequately controlled acromegaly. This was a prospective, randomized open label clinical trial. Forty-four patients (22 per group) completed the study; where participants received either cabergoline (3 mg/week) or raloxifene (60 mg twice daily) add-on therapy for 12 weeks in a parallel manner. The primary outcome was the rate of reduction in serum insulin-like growth factor 1 (IGF-1) from baseline. Secondary outcomes comprised normalization of serum IGF-1 for age and sex. Serum IGF-1 was significantly decreased in both the cabergoline (40.3 ± 25.6%, P<.001) and raloxifene (31.5 ± 24.6%, P<.001) groups, with no significant difference between arms ( P>.05). Normalization in serum IGF-1 values occurred in 40.9% of patients who were on cabergoline compared to 45.5% of those receiving raloxifene ( P = .76). The subsequent logistic regression analysis highlighted baseline IGF-1 as a significant predictor of IGF-1 normalization (odds ratio, 0.995; 95% confidence interval, 0.990-0.999; P = .02). Using the receiver operating characteristic (ROC) curve analysis for the entire group, the baseline IGF-1 value of 1.47 the upper limit of normal (ULN) was the best cut-off point to identify patients with normal IGF-1 at the end of the study (sensitivity: 52.6%, specificity: 84.0%, Yoden's index: 0.366). Full biochemical control of acromegaly was achieved in 22.7% of patients in the cabergoline group compared to 13.6% of those in the raloxifene group ( P = .43). Cabergoline and raloxifene add-on therapy could effectively decrease serum IGF-1 level in patients with inadequately controlled acromegaly. The efficacy profiles of both drugs are comparable. DA = dopamine agonist; FBG = fasting blood glucose; GH = growth hormone; IGF1 = insulin-like growth factor-1; IQR = interquartile range; OR = odds ratio; ROC = receiver operating characteristic; SA = somatostatin analogue; SERM = selective estrogen modulator receptor; ULN = upper limit of normal.

E-cadherin expression is associated with the response to somatostatin analogues in patients with acromegaly

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